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Banahene N, Kavunja HW, Swarts BM. Chemical Reporters for Bacterial Glycans: Development and Applications. Chem Rev 2022; 122:3336-3413. [PMID: 34905344 PMCID: PMC8958928 DOI: 10.1021/acs.chemrev.1c00729] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacteria possess an extraordinary repertoire of cell envelope glycans that have critical physiological functions. Pathogenic bacteria have glycans that are essential for growth and virulence but are absent from humans, making them high-priority targets for antibiotic, vaccine, and diagnostic development. The advent of metabolic labeling with bioorthogonal chemical reporters and small-molecule fluorescent reporters has enabled the investigation and targeting of specific bacterial glycans in their native environments. These tools have opened the door to imaging glycan dynamics, assaying and inhibiting glycan biosynthesis, profiling glycoproteins and glycan-binding proteins, and targeting pathogens with diagnostic and therapeutic payload. These capabilities have been wielded in diverse commensal and pathogenic Gram-positive, Gram-negative, and mycobacterial species─including within live host organisms. Here, we review the development and applications of chemical reporters for bacterial glycans, including peptidoglycan, lipopolysaccharide, glycoproteins, teichoic acids, and capsular polysaccharides, as well as mycobacterial glycans, including trehalose glycolipids and arabinan-containing glycoconjugates. We cover in detail how bacteria-targeting chemical reporters are designed, synthesized, and evaluated, how they operate from a mechanistic standpoint, and how this information informs their judicious and innovative application. We also provide a perspective on the current state and future directions of the field, underscoring the need for interdisciplinary teams to create novel tools and extend existing tools to support fundamental and translational research on bacterial glycans.
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2
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Lin H, Yang C, Wang W. Imitate to illuminate: labeling of bacterial peptidoglycan with fluorescent and bio-orthogonal stem peptide-mimicking probes. RSC Chem Biol 2022; 3:1198-1208. [PMID: 36320889 PMCID: PMC9533424 DOI: 10.1039/d2cb00086e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/01/2022] [Indexed: 11/30/2022] Open
Abstract
Because of its high involvement in antibiotic therapy and the emergence of drug-resistance, the chemical structure and biosynthesis of bacterial peptidoglycan (PGN) have been some of the key topics in bacteriology for several decades. Recent advances in the development of fluorescent or bio-orthogonal stem peptide-mimicking probes for PGN-labeling have rekindled the interest of chemical biologists and microbiologists in this area. The structural designs, bio-orthogonal features and flexible uses of these peptide-based probes allow directly assessing, not only the presence of PGN in different biological systems, but also specific steps in PGN biosynthesis. In this review, we summarize the design rationales, functioning mechanisms, and microbial processes/questions involved in these PGN-targeting probes. Our perspectives on the limitations and future development of these tools are also presented. By imitating the structures of stem peptide, many fluorescent and bio-orthogonal labeling probes have been designed and used in illuminating the peptidoglycan biosynthesis processes.![]()
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Affiliation(s)
- Huibin Lin
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Chaoyong Yang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Key Laboratory for Chemical Biology of Fujian Province State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Wei Wang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
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3
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Liechti GW. Localized Peptidoglycan Biosynthesis in Chlamydia trachomatis Conforms to the Polarized Division and Cell Size Reduction Developmental Models. Front Microbiol 2021; 12:733850. [PMID: 34956109 PMCID: PMC8699169 DOI: 10.3389/fmicb.2021.733850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
Cell size regulation in bacteria is a function of two basic cellular processes: the expansion of the cell envelope and its constriction at spatially defined points at what will eventually become the division plane. In most bacterial species, both cell wall expansion and restriction are dependent on peptidoglycan (PG), a structural polymer comprised of sugars and amino acids that imparts strength and rigidity to bacterial membranes. Pathogenic Chlamydia species are unique in that their cell walls contain very little PG, which is restricted almost entirely to the apparent division plane of the microbe's replicative forms. Very little is known about the degree to which PG affects the size and shape of C. trachomatis during its division process, and recent studies suggest the process is initiated via a polarized mechanism. We conducted an imaging study to ascertain the dimensions, orientation, and relative density of chlamydial PG throughout the organism's developmental cycle. Our analysis indicates that PG in replicating C. trachomatis can be associated with four, broad structural forms; polar/septal disks, small/thick rings, large rings, and small/thin rings. We found that PG density appeared to be highest in septal disks and small/thick rings, indicating that these structures likely have high PG synthesis to degradation ratios. We also discovered that as C. trachomatis progresses through its developmental cycle PG structures, on average, decrease in total volume, indicating that the average cell volume of chlamydial RBs likely decreases over time. When cells infected with C. trachomatis are treated with inhibitors of critical components of the microbe's two distinct PG synthases, we observed drastic differences in the ratio of PG synthesis to degradation, as well as the volume and shape of PG-containing structures. Overall, our results suggest that C. trachomatis PG synthases differentially regulate the expansion and contraction of the PG ring during both the expansion and constriction of the microbe's cell membrane during cell growth and division, respectively.
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Affiliation(s)
- George W Liechti
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States
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4
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Genome copy number regulates inclusion expansion, septation, and infectious developmental form conversion in Chlamydia trachomatis. J Bacteriol 2021; 203:JB.00630-20. [PMID: 33431433 PMCID: PMC8095454 DOI: 10.1128/jb.00630-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
DNA replication is essential for the growth and development of Chlamydia trachomatis, however it is unclear how this process contributes to and is controlled by the pathogen's biphasic lifecycle. While inhibitors of transcription, translation, cell division, and glucose-6-phosphate transport all negatively affect chlamydial intracellular development, the effects of directly inhibiting DNA polymerase have never been examined. We isolated a temperature sensitive dnaE mutant (dnaEts ) that exhibits a ∼100-fold reduction in genome copy number at the non-permissive temperature (40°C), but replicates similarly to the parent at the permissive temperature of 37°C. We measured higher ratios of genomic DNA nearer the origin of replication than the terminus in dnaEts at 40°C, indicating that this replication deficiency is due to a defect in DNA polymerase processivity. dnaEts formed fewer and smaller pathogenic vacuoles (inclusions) at 40°C, and the bacteria appeared enlarged and exhibited defects in cell division. The bacteria also lacked both discernable peptidoglycan and polymerized MreB, the major cell division organizing protein in Chlamydia responsible for nascent peptidoglycan biosynthesis. We also found that absolute genome copy number, rather than active genome replication, was sufficient for infectious progeny production. Deficiencies in both genome replication and inclusion expansion reversed when dnaEts was shifted from 40°C to 37°C early in infection, and intragenic suppressor mutations in dnaE also restored dnaEts genome replication and inclusion expansion at 40°C. Overall, our results show that genome replication in C. trachomatis is required for inclusion expansion, septum formation, and the transition between the microbe's replicative and infectious forms.SIGNIFICANCE Chlamydiae transition between infectious, extracellular elementary bodies (EBs) and non-infectious, intracellular reticulate bodies (RBs). Some checkpoints that govern transitions in chlamydial development have been identified, but the extent to which genome replication plays a role in regulating the pathogen's infectious cycle has not been characterized. We show that genome replication is dispensable for EB to RB conversion, but is necessary for RB proliferation, division septum formation, and inclusion expansion. We use new methods to investigate developmental checkpoints and dependencies in Chlamydia that facilitate the ordering of events in the microbe's biphasic life cycle. Our findings suggest that Chlamydia utilizes feedback inhibition to regulate core metabolic processes during development, likely an adaptation to intracellular stress and a nutrient-limiting environment.
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Elgamoudi BA, Taha T, Korolik V. Inhibition of Campylobacter jejuni Biofilm Formation by D-Amino Acids. Antibiotics (Basel) 2020; 9:E836. [PMID: 33238583 PMCID: PMC7700173 DOI: 10.3390/antibiotics9110836] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022] Open
Abstract
The ability of bacterial pathogens to form biofilms is an important virulence mechanism in relation to their pathogenesis and transmission. Biofilms play a crucial role in survival in unfavorable environmental conditions, acting as reservoirs of microbial contamination and antibiotic resistance. For intestinal pathogen Campylobacter jejuni, biofilms are considered to be a contributing factor in transmission through the food chain and currently, there are no known methods for intervention. Here, we present an unconventional approach to reducing biofilm formation by C. jejuni by the application of D-amino acids (DAs), and L-amino acids (LAs). We found that DAs and not LAs, except L-alanine, reduced biofilm formation by up to 70%. The treatment of C. jejuni cells with DAs changed the biofilm architecture and reduced the appearance of amyloid-like fibrils. In addition, a mixture of DAs enhanced antimicrobial efficacy of D-Cycloserine (DCS) up to 32% as compared with DCS treatment alone. Unexpectedly, D-alanine was able to reverse the inhibitory effect of other DAs as well as that of DCS. Furthermore, L-alanine and D-tryptophan decreased transcript levels of peptidoglycan biosynthesis enzymes alanine racemase (alr) and D-alanine-D-alanine ligase (ddlA) while D-serine was only able to decrease the transcript levels of alr. Our findings suggest that a combination of DAs could reduce biofilm formation, viability and persistence of C. jejuni through dysregulation of alr and ddlA.
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Affiliation(s)
| | | | - Victoria Korolik
- Institute for Glycomics, Griffith University, Gold Coast QLD 4222, Australia; (B.A.E.); (T.T.)
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6
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Penicillin-binding proteins regulate multiple steps in the polarized cell division process of Chlamydia. Sci Rep 2020; 10:12588. [PMID: 32724139 PMCID: PMC7387471 DOI: 10.1038/s41598-020-69397-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 07/08/2020] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis serovar L2 and Chlamydia muridarum, which do not express FtsZ, undergo polarized cell division. During division, peptidoglycan assembles at the pole of dividing Chlamydia trachomatis cells where daughter cell formation occurs, and peptidoglycan regulates at least two distinct steps in the polarized division of Chlamydia trachomatis and Chlamydia muridarum. Cells treated with inhibitors that prevent peptidoglycan synthesis or peptidoglycan crosslinking by penicillin-binding protein 2 (PBP2) are unable to initiate polarized division, while cells treated with inhibitors that prevent peptidoglycan crosslinking by penicillin-binding protein 3 (PBP3/FtsI) initiate polarized division, but the process arrests at an early stage of daughter cell growth. Consistent with their distinct roles in polarized division, peptidoglycan organization is different in cells treated with PBP2 and PBP3-specific inhibitors. Our analyses indicate that the sequential action of PBP2 and PBP3 drives changes in peptidoglycan organization that are essential for the polarized division of these obligate intracellular bacteria. Furthermore, the roles we have characterized for PBP2 and PBP3 in regulating specific steps in chlamydial cell division have not been described in other bacteria.
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Gitsels A, Van Lent S, Sanders N, Vanrompay D. Chlamydia: what is on the outside does matter. Crit Rev Microbiol 2020; 46:100-119. [PMID: 32093536 DOI: 10.1080/1040841x.2020.1730300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review summarises major highlights on the structural biology of the chlamydial envelope. Chlamydiae are obligate intracellular bacteria, characterised by a unique biphasic developmental cycle. Depending on the stage of their lifecycle, they appear in the form of elementary or reticulate bodies. Since these particles have distinctive functions, it is not surprising that their envelope differs in lipid as well as in protein content. Vice versa, by identifying surface proteins, specific characteristics of the particles such as rigidity or immunogenicity may be deduced. Detailed information on the bacterial membranes will increase our understanding on the host-pathogen interactions chlamydiae employ to survive and grow and might lead to new strategies to battle chlamydial infections.
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Affiliation(s)
- Arlieke Gitsels
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sarah Van Lent
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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8
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Hsu YP, Booher G, Egan A, Vollmer W, VanNieuwenhze MS. d-Amino Acid Derivatives as in Situ Probes for Visualizing Bacterial Peptidoglycan Biosynthesis. Acc Chem Res 2019; 52:2713-2722. [PMID: 31419110 DOI: 10.1021/acs.accounts.9b00311] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The bacterial cell wall is composed of membrane layers and a rigid yet flexible scaffold called peptidoglycan (PG). PG provides mechanical strength to enable bacteria to resist damage from the environment and lysis due to high internal turgor. PG also has a critical role in dictating bacterial cell morphology. The essential nature of PG for bacterial propagation, as well as its value as an antibiotic target, has led to renewed interest in the study of peptidoglycan biosynthesis. However, significant knowledge gaps remain that must be addressed before a clear understanding of peptidoglycan synthesis and dynamics is realized. For example, the enzymes involved in the PG biosynthesis pathway have not been fully characterized. Our understanding of PG biosynthesis has been frequently revamped by the discovery of novel enzymes or newly characterized functions of known enzymes. In addition, we do not clearly know how the respective activities of these enzymes are coordinated with each other and how they control the spatial and temporal dynamics of PG synthesis. The emergence of molecular probes and imaging techniques has significantly advanced the study PG synthesis and modification. Prior efforts utilized the specificity of PG-targeting antibiotics and proteins to develop PG-specific probes, such as fluorescent vancomycin and fluorescent wheat germ agglutinin. However, these probes suffer from limitations due to toxic effects toward bacterial cells and poor membrane permeability. To address these issues, we designed and introduced a family of novel molecular probes, fluorescent d-amino acids (FDAAs), which are covalently incorporated into PG through the activities of endogenous bacterial transpeptidases. Their high biocompatibility and PG specificity have made them powerful tools for labeling peptidoglycan. In addition, their enzyme-mediated incorporation faithfully reflects the activity of PG synthases, providing a direct in situ method for studying PG formation during the bacterial life cycle. In this Account, we describe our efforts directed at the development of FDAAs and their derivatives. These probes have enabled for the first time the ability to visualize PG synthesis in live bacterial cells and in real time. We summarize experimental evidence for FDAA incorporation into PG and the enzyme-mediated incorporation pathway. We demonstrate various applications of FDAAs, including bacterial morphology analyses, PG growth model studies, investigation of PG-enzyme correlation, in vitro PG synthase activity assays, and antibiotic inhibition tests. Finally, we discuss the current limitations of the probes and our ongoing efforts to improve them. We are confident that these probes will prove to be valuable tools that will enable the discovery of new antibiotic targets and expand the available arsenal directed at the public health threat posed by antibiotic resistance.
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Affiliation(s)
- Yen-Pang Hsu
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Simon Hall 001, 212 South Hawthorne Drive, Bloomington, Indiana 47405, United States
| | - Garrett Booher
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Simon Hall 001, 212 South Hawthorne Drive, Bloomington, Indiana 47405, United States
| | - Alexander Egan
- The Centre for Bacterial Cell Biology, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, United Kingdom
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, United Kingdom
| | - Michael S. VanNieuwenhze
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Simon Hall 001, 212 South Hawthorne Drive, Bloomington, Indiana 47405, United States
- Department of Chemistry, Indiana University Bloomington, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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9
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Abstract
The evolutionary separated Gram-negative Chlamydiales show a biphasic life cycle and replicate exclusively within eukaryotic host cells. Members of the genus Chlamydia are responsible for many acute and chronic diseases in humans, and Chlamydia-related bacteria are emerging pathogens. We revisit past efforts to detect cell wall material in Chlamydia and Chlamydia-related bacteria in the context of recent breakthroughs in elucidating the underlying cellular and molecular mechanisms of the chlamydial cell wall biosynthesis. In this review, we also discuss the role of cell wall biosynthesis in chlamydial FtsZ-independent cell division and immune modulation. In the past, penicillin susceptibility of an invisible wall was referred to as the "chlamydial anomaly." In light of new mechanistic insights, chlamydiae may now emerge as model systems to understand how a minimal and modified cell wall biosynthetic machine supports bacterial cell division and how cell wall-targeting beta-lactam antibiotics can also act bacteriostatically rather than bactericidal. On the heels of these discussions, we also delve into the effects of other cell wall antibiotics in individual chlamydial lineages.
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10
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Abstract
Peptidoglycan is an essential component of the cell wall that protects bacteria from environmental stress. A carefully coordinated biosynthesis of peptidoglycan during cell elongation and division is required for cell viability. This biosynthesis involves sophisticated enzyme machineries that dynamically synthesize, remodel, and degrade peptidoglycan. However, when and where bacteria build peptidoglycan, and how this is coordinated with cell growth, have been long-standing questions in the field. The improvement of microscopy techniques has provided powerful approaches to study peptidoglycan biosynthesis with high spatiotemporal resolution. Recent development of molecular probes further accelerated the growth of the field, which has advanced our knowledge of peptidoglycan biosynthesis dynamics and mechanisms. Here, we review the technologies for imaging the bacterial cell wall and its biosynthesis activity. We focus on the applications of fluorescent d-amino acids, a newly developed type of probe, to visualize and study peptidoglycan synthesis and dynamics, and we provide direction for prospective research.
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Affiliation(s)
- Atanas D Radkov
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.,Current affiliation: Biophysics and Biochemistry Department, University of California, San Francisco, California 94158, USA;
| | - Yen-Pang Hsu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA; , ,
| | - Garrett Booher
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA; , ,
| | - Michael S VanNieuwenhze
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA; , ,
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11
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Atwal S, Giengkam S, Chaemchuen S, Dorling J, Kosaisawe N, VanNieuwenhze M, Sampattavanich S, Schumann P, Salje J. Evidence for a peptidoglycan-like structure in Orientia tsutsugamushi. Mol Microbiol 2017; 105:440-452. [PMID: 28513097 PMCID: PMC5523937 DOI: 10.1111/mmi.13709] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2017] [Indexed: 01/04/2023]
Abstract
Bacterial cell walls are composed of the large cross-linked macromolecule peptidoglycan, which maintains cell shape and is responsible for resisting osmotic stresses. This is a highly conserved structure and the target of numerous antibiotics. Obligate intracellular bacteria are an unusual group of organisms that have evolved to replicate exclusively within the cytoplasm or vacuole of a eukaryotic cell. They tend to have reduced amounts of peptidoglycan, likely due to the fact that their growth and division takes place within an osmotically protected environment, and also due to a drive to reduce activation of the host immune response. Of the two major groups of obligate intracellular bacteria, the cell wall has been much more extensively studied in the Chlamydiales than the Rickettsiales. Here, we present the first detailed analysis of the cell envelope of an important but neglected member of the Rickettsiales, Orientia tsutsugamushi. This bacterium was previously reported to completely lack peptidoglycan, but here we present evidence supporting the existence of a peptidoglycan-like structure in Orientia, as well as an outer membrane containing a network of cross-linked proteins, which together confer cell envelope stability. We find striking similarities to the unrelated Chlamydiales, suggesting convergent adaptation to an obligate intracellular lifestyle.
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Affiliation(s)
- Sharanjeet Atwal
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Suwittra Chaemchuen
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Jack Dorling
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Nont Kosaisawe
- Siriraj Laboratory for Systems Pharmacology, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand
| | | | - Somponnat Sampattavanich
- Siriraj Laboratory for Systems Pharmacology, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand
| | - Peter Schumann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jeanne Salje
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
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12
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Hsu YP, Meng X, VanNieuwenhze M. Methods for visualization of peptidoglycan biosynthesis. METHODS IN MICROBIOLOGY 2016. [DOI: 10.1016/bs.mim.2016.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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13
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Structural characterization of muropeptides from Chlamydia trachomatis peptidoglycan by mass spectrometry resolves "chlamydial anomaly". Proc Natl Acad Sci U S A 2015; 112:11660-5. [PMID: 26290580 DOI: 10.1073/pnas.1514026112] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The "chlamydial anomaly," first coined by James Moulder, describes the inability of researchers to detect or purify peptidoglycan (PG) from pathogenic Chlamydiae despite genetic and biochemical evidence and antibiotic susceptibility data that suggest its existence. We recently detected PG in Chlamydia trachomatis by a new metabolic cell wall labeling method, however efforts to purify PG from pathogenic Chlamydiae have remained unsuccessful. Pathogenic chlamydial species are known to activate nucleotide-binding oligomerization domain-containing protein 2 (NOD2) innate immune receptors by as yet uncharacterized ligands, which are presumed to be PG fragments (muramyl di- and tripeptides). We used the NOD2-dependent activation of NF-κB by C. trachomatis-infected cell lysates as a biomarker for the presence of PG fragments within specific lysate fractions. We designed a new method of muropeptide isolation consisting of a double filtration step coupled with reverse-phase HPLC fractionation of Chlamydia-infected HeLa cell lysates. Fractions that displayed NOD2 activity were analyzed by electrospray ionization mass spectrometry, confirming the presence of muramyl di- and tripeptides in Chlamydia-infected cell lysate fractions. Moreover, the mass spectrometry data of large muropeptide fragments provided evidence that transpeptidation and transglycosylation reactions occur in pathogenic Chlamydiae. These results reveal the composition of chlamydial PG and disprove the "glycanless peptidoglycan" hypothesis.
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Abdelsayed S, Ha Duong N, Hai J, Hémadi M, El Hage Chahine J, Verbeke P, Serradji N. Design and synthesis of 3-isoxazolidone derivatives as new Chlamydia trachomatis inhibitors. Bioorg Med Chem Lett 2014; 24:3854-60. [DOI: 10.1016/j.bmcl.2014.06.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/17/2014] [Accepted: 06/19/2014] [Indexed: 12/19/2022]
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15
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De Benedetti S, Bühl H, Gaballah A, Klöckner A, Otten C, Schneider T, Sahl HG, Henrichfreise B. Characterization of serine hydroxymethyltransferase GlyA as a potential source of D-alanine in Chlamydia pneumoniae. Front Cell Infect Microbiol 2014; 4:19. [PMID: 24616885 PMCID: PMC3935232 DOI: 10.3389/fcimb.2014.00019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/03/2014] [Indexed: 01/08/2023] Open
Abstract
For intracellular Chlamydiaceae, there is no need to withstand osmotic challenges, and a functional cell wall has not been detected in these pathogens so far. Nevertheless, penicillin inhibits cell division in Chlamydiaceae resulting in enlarged aberrant bodies, a phenomenon known as chlamydial anomaly. D-alanine is a unique and essential component in the biosynthesis of bacterial cell walls. In free-living bacteria like Escherichia coli, penicillin-binding proteins such as monofunctional transpeptidases PBP2 and PBP3, the putative targets of penicillin in Chlamydiaceae, cross-link adjacent peptidoglycan strands via meso-diaminopimelic acid and D-Ala-D-Ala moieties of pentapeptide side chains. In the absence of genes coding for alanine racemase Alr and DadX homologs, the source of D-Ala and thus the presence of substrates for PBP2 and PBP3 activity in Chlamydiaceae has puzzled researchers for years. Interestingly, Chlamydiaceae genomes encode GlyA, a serine hydroxymethyltransferase that has been shown to exhibit slow racemization of D- and L-alanine as a side reaction in E. coli. We show that GlyA from Chlamydia pneumoniae can serve as a source of D-Ala. GlyA partially reversed the D-Ala auxotrophic phenotype of an E. coli racemase double mutant. Moreover, purified chlamydial GlyA had racemase activity on L-Ala in vitro and was inhibited by D-cycloserine, identifying GlyA, besides D-Ala ligase MurC/Ddl, as an additional target of this competitive inhibitor in Chlamydiaceae. Proof of D-Ala biosynthesis in Chlamydiaceae helps to clarify the structure of cell wall precursor lipid II and the role of chlamydial penicillin-binding proteins in the development of non-dividing aberrant chlamydial bodies and persistence in the presence of penicillin.
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Affiliation(s)
- Stefania De Benedetti
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Henrike Bühl
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Ahmed Gaballah
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Anna Klöckner
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Christian Otten
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Tanja Schneider
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Hans-Georg Sahl
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
| | - Beate Henrichfreise
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn Bonn, Germany
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Liechti GW, Kuru E, Hall E, Kalinda A, Brun YV, VanNieuwenhze M, Maurelli AT. A new metabolic cell-wall labelling method reveals peptidoglycan in Chlamydia trachomatis. Nature 2013; 506:507-10. [PMID: 24336210 PMCID: PMC3997218 DOI: 10.1038/nature12892] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/21/2013] [Indexed: 12/16/2022]
Abstract
Peptidoglycan (PG), an essential structure in the cell walls of the vast majority of bacteria, is critical for division and maintaining cell shape and hydrostatic pressure. Bacteria comprising the Chlamydiales were thought to be one of the few exceptions. Chlamydia harbour genes for PG biosynthesis and exhibit susceptibility to 'anti-PG' antibiotics, yet attempts to detect PG in any chlamydial species have proven unsuccessful (the 'chlamydial anomaly'). We used a novel approach to metabolically label chlamydial PG using d-amino acid dipeptide probes and click chemistry. Replicating Chlamydia trachomatis were labelled with these probes throughout their biphasic developmental life cycle, and the results of differential probe incorporation experiments conducted in the presence of ampicillin are consistent with the presence of chlamydial PG-modifying enzymes. These findings culminate 50 years of speculation and debate concerning the chlamydial anomaly and are the strongest evidence so far that chlamydial species possess functional PG.
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Affiliation(s)
- G W Liechti
- 1] Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, USA [2]
| | - E Kuru
- 1] Interdisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405, USA [2]
| | - E Hall
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - A Kalinda
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Y V Brun
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - M VanNieuwenhze
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - A T Maurelli
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, USA
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Borges V, Ferreira R, Nunes A, Nogueira P, Borrego MJ, Gomes JP. Normalization strategies for real-time expression data in Chlamydia trachomatis. J Microbiol Methods 2010; 82:256-64. [PMID: 20619305 DOI: 10.1016/j.mimet.2010.06.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/24/2010] [Accepted: 06/29/2010] [Indexed: 11/26/2022]
Abstract
Chlamydia trachomatis is a widespread obligate intracellular pathogen genetically non-tractable for which transcriptomics is a fundamental tool to better understand its biology. However, the suitability of endogenous controls for normalization of transcriptomic data in this bacterium still needs validation. We aimed to assess the stability of 10 genes for their potential use as endogenous controls in real-time quantitative PCR assays at both normal and stress (D-cycloserine treatment) growth conditions throughout the developmental cycle of three C. trachomatis strains with different tissue tropism. Normalization was performed by real-time absolute quantification of the bacterial genomes. We also tested the applicability of two widely used softwares (geNorm and Normfinder) to our data. For all strains, we found that 16SrRNA was the most stably expressed gene throughout the chlamydial normal developmental cycle, which indicates its potential use as endogenous control in relative expression assays. However, it was highly unstable under D-cycloserine treatment (where oppA_2 was top-ranked), suggesting prudence when using ribosomal genes in expression experiments involving stress conditions. The geNorm and Normfinder algorithms revealed contrasting results and seem inappropriate for the selected pool of genes. Considering the multiplicity of experimental conditions, there should be an in loco validation of endogenous controls, where 16SrRNA appears to be in the front line. Alternatively, normalization of expression data against genomic DNA, which is less influenced by experimental constraints that are especially relevant for intracellular organisms, likely constitutes a good option. Moreover, the number of genomes also seems to be less subject to variation than expression of endogenous controls when working under stress conditions. The present study constitutes the first evaluation of putative endogenous controls for real-time expression assays in C. trachomatis.
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Affiliation(s)
- V Borges
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016-Lisbon, Portugal
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Abstract
Biochemical events accompanying changes in structure and behavior of the cell walls of Chlamydia psittaci strain 6BC during its developmental cycle in L cells (mouse fibroblasts) were studied by measuring at short intervals the effect of d-cycloserine and penicillin G on incorporation of labeled intermediates into acid-insoluble fractions of infected L cells in which host incorporation had been inhibited by cycloheximide and into intact chlamydial cells and cell walls separated from the infected L cells. d-Cycloserine enhanced the incorporation of (14)C-l-alanine at all times in the developmental cycle, but the incorporation of (14)C-l-lysine was always inhibited. In parallel experiments, penicillin G had no effect on incorporation of any of these intermediates, but when infected L cells incorporated (14)C-l-alanine in the presence of penicillin G, the labeled alanine was released more rapidly in the subsequent absence of the antibiotic than in its continued presence. When either penicillin G or d-cycloserine was present throughout the developmental cycle, C. psittaci continued to synthesize deoxyribonucleic acid and protein, but at less than normal rates.
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Affiliation(s)
- I I Tribby
- Department of Microbiology, The University of Chicago, Chicago, Illinois 60637
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McCoy AJ, Maurelli AT. Building the invisible wall: updating the chlamydial peptidoglycan anomaly. Trends Microbiol 2006; 14:70-7. [PMID: 16413190 DOI: 10.1016/j.tim.2005.12.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 11/25/2005] [Accepted: 12/20/2005] [Indexed: 11/22/2022]
Abstract
The existence of peptidoglycan (PG) in chlamydiae has long been debated. Genome sequencing of members of the Chlamydiaceae family and Protochlamydia amoebophila has uncovered a nearly complete pathway for PG synthesis in these organisms. The recent use of microarray and proteomic analysis methods has revealed that PG synthesis genes are expressed primarily during reticulate body development and division. Furthermore, key genes in the chlamydial PG synthesis pathway encode functional PG synthesis enzymes, some of which provide the basis for the susceptibility of chlamydiae to PG inhibitors. Recent studies shed light on how the construction of a cell wall in chlamydiae is taking shape and why the wall is being built.
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Affiliation(s)
- Andrea J McCoy
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799, USA
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McCoy AJ, Maurelli AT. Characterization of Chlamydia MurC-Ddl, a fusion protein exhibiting D-alanyl-D-alanine ligase activity involved in peptidoglycan synthesis and D-cycloserine sensitivity. Mol Microbiol 2005; 57:41-52. [PMID: 15948948 DOI: 10.1111/j.1365-2958.2005.04661.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recent characterization of chlamydial genes encoding functional peptidoglycan (PG)-synthesis proteins suggests that the Chlamydiaceae possess the ability to synthesize PG yet biochemical evidence for the synthesis of PG has yet to be demonstrated. The presence of D-amino acids in PG is a hallmark of bacteria. Chlamydiaceae do not appear to encode amino acid racemases however, a D-alanyl-D-alanine (D-Ala-D-Ala) ligase homologue (Ddl) is encoded in the genome. Thus, we undertook a genetics-based approach to demonstrate and characterize the D-Ala-D-Ala ligase activity of chlamydial Ddl, a protein encoded as a fusion with MurC. The full-length murC-ddl fusion gene from Chlamydia trachomatis serovar L2 was cloned and placed under the control of the arabinose-inducible ara promoter and transformed into a D-Ala-D-Ala ligase auxotroph of Escherichia coli possessing deletions of both the ddlA and ddlB genes. Viability of the E. coliDeltaddlADeltaddlB mutant in the absence of exogenous D-Ala-D-Ala dipeptide became dependent on the expression of the chlamydial murC-ddl thus demonstrating functional ligase activity. Domain mapping of the full-length fusion protein and site-directed mutagenesis of the MurC domain revealed that the structure of the full fusion protein but not MurC enzymatic activity was required for ligase activity in vivo. Recombinant MurC-Ddl exhibited substrate specificity for D-Ala. Chlamydia growth is inhibited by D-cycloserine (DCS) and in vitro analysis provided evidence for the chlamydial MurC-Ddl as the target for DCS sensitivity. In vivo sensitivity to DCS could be reversed by addition of exogenous D-Ala and D-Ala-D-Ala. Together, these findings further support our hypothesis that PG is synthesized by members of the Chlamydiaceae family and suggest that D-amino acids, specifically D-Ala, are present in chlamydial PG.
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Affiliation(s)
- Andrea J McCoy
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road Bethesda, MD 20814-4799, USA
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Binet R, Maurelli AT. Frequency of spontaneous mutations that confer antibiotic resistance in Chlamydia spp. Antimicrob Agents Chemother 2005; 49:2865-73. [PMID: 15980362 PMCID: PMC1168699 DOI: 10.1128/aac.49.7.2865-2873.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations in rRNA genes (rrn) that confer resistance to ribosomal inhibitors are typically recessive or weakly codominant and have been mostly reported for clinical strains of pathogens possessing only one or two rrn operons, such as Helicobacter pylori and Mycobacterium spp. An analysis of the genome sequences of several members of the Chlamydiaceae revealed that these obligate intracellular bacteria harbor only one or two sets of rRNA genes. To study the contribution of rRNA mutations to the emergence of drug resistance in the Chlamydiaceae, we used the sensitivities of Chlamydia trachomatis L2 (two rrn operons) and Chlamydophila psittaci 6BC (one rrn operon) to the aminoglycoside spectinomycin as a model. Confluent cell monolayers were infected in a plaque assay with about 10(8) wild-type infectious particles and then treated with the antibiotic. After a 2-week incubation time, plaques formed by spontaneous spectinomycin-resistant (Spc(r)) mutants appeared with a frequency of 5 x 10(-5) for C. psittaci 6BC. No Spc(r) mutants were isolated for C. trachomatis L2, although the frequencies of rifampin resistance were in the same range for both strains (i.e., 10(-7)). The risk of emergence of Chlamydia strains resistant to tetracyclines and macrolides, the ribosomal drugs currently used to treat chlamydial infections, is discussed.
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Affiliation(s)
- Rachel Binet
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799,USA
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Abstract
Moulder, James W. (University of Chicago, Chicago, Ill.), Dorothy L. Novosel, and Ilse C. Tribby. Diaminopimelic acid decarboxylase of the agent of meningopneumonitis. J. Bacteriol. 85:701-706. 1963.-Evidence is presented for the presence in meningopneumonitis particles and extracts of an enzyme decarboxylating alpha, epsilon-diaminopimelic acid to lysine and for the absence of a corresponding enzyme in the uninfected host. Properties of the enzyme are described and compared with those of bacterial diaminopimelic acid decarboxylases. The significance of these observations with respect to the mode of lysine biosynthesis in the psittacosis group and to its phylogenetic origin is pointed out.
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MOULDER JW, NOVOSEL DL, TRIBBY II. CHANGES IN MOUSE PNEUMONITIS AGENT ASSOCIATED WITH DEVELOPMENT OF RESISTANCE TO CHLORTETRACYCLINE. J Bacteriol 1996; 89:17-22. [PMID: 14255660 PMCID: PMC315542 DOI: 10.1128/jb.89.1.17-22.1965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Moulder, James W. (University of Chicago, Chicago, Ill.), Dorothy L. Novosel, and Ilse I. E. Tribby. Changes in mouse pneumonitis agent associated with development of resistance to chlortetracycline. J. Bacteriol. 89:17-22. 1965.-A chlortetracycline-resistant mutant of mouse pneumonitis agent, a member of the psittacosis group of microorganisms, differed in several ways from the susceptible stock from which it had been derived by serial chick-embryo passage in the presence of the antibiotic. It was almost completely resistant to chlortetracycline, had a longer growth cycle, produced many more very large particles, was not neutralized by parent antiserum and vice versa, was 10 times as resistant to d-cycloserine, and was highly lethal to mice when inoculated intracerebrally. These changes probably do not occur independently of one another but are the reflection of some genetically controlled change in the surface structure of the mouse pneumonitis particle which enables the resistant mutant to multiply in the presence of chlortetracycline.
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Beatty WL, Morrison RP, Byrne GI. Persistent chlamydiae: from cell culture to a paradigm for chlamydial pathogenesis. Microbiol Rev 1994; 58:686-99. [PMID: 7854252 PMCID: PMC372987 DOI: 10.1128/mr.58.4.686-699.1994] [Citation(s) in RCA: 281] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chlamydiae are medically important bacteria responsible for a wide range of human infections and diseases. Repeated episodes of infection promote chronic inflammation associated with detrimental immune system-mediated pathologic changes. However, the true nature of chlamydial pathogenesis may encompass repeated infection superimposed upon persistent infection, which would allow for heightened immune reactivity. During the course of chlamydial infection, numerous host elaborated factors with inhibitory or modifying effects may cause alterations in the chlamydia-host cell relationship such that the organism is maintained in a nonproductive stage of growth. Abnormal or persistent chlamydiae have been recognized under a variety of cell culture systems. The numerous factors associated with altered growth suggest an innate flexibility in the developmental cycle of chlamydiae. This review evaluates in vitro studies of chlamydial persistence and correlates these model systems to features of natural chlamydial disease.
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Affiliation(s)
- W L Beatty
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison 53706
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Abstract
The obligately intracellular bacteria of the genus Chlamydia, which is only remotely related to other eubacterial genera, cause many diseases of humans, nonhuman mammals, and birds. Interaction of chlamydiae with host cells in vitro has been studied as a model of infection in natural hosts and as an example of the adaptation of an organism to an unusual environment, the inside of another living cell. Among the novel adaptations made by chlamydiae have been the substitution of disulfide-bond-cross-linked polypeptides for peptidoglycans and the use of host-generated nucleotide triphosphates as sources of metabolic energy. The effect of contact between chlamydiae and host cells in culture varies from no effect at all to rapid destruction of either chlamydiae or host cells. When successful infection occurs, it is usually followed by production of large numbers of progeny and destruction of host cells. However, host cells containing chlamydiae sometimes continue to divide, with or without overt signs of infection, and chlamydiae may persist indefinitely in cell cultures. Some of the many factors that influence the outcome of chlamydia-host cell interaction are kind of chlamydiae, kind of host cells, mode of chlamydial entry, nutritional adequacy of the culture medium, presence of antimicrobial agents, and presence of immune cells and soluble immune factors. General characteristics of chlamydial multiplication in cells of their natural hosts are reproduced in established cell lines, but reproduction in vitro of the subtle differences in chlamydial behavior responsible for the individuality of the different chlamydial diseases will require better in vitro models.
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Affiliation(s)
- J W Moulder
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
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26
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Studies in vitro of the nature and synthesis of the cell wall ofChlamydia trachomatis. Curr Microbiol 1984. [DOI: 10.1007/bf01577140] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Barbour AG, Amano K, Hackstadt T, Perry L, Caldwell HD. Chlamydia trachomatis has penicillin-binding proteins but not detectable muramic acid. J Bacteriol 1982; 151:420-8. [PMID: 7085567 PMCID: PMC220254 DOI: 10.1128/jb.151.1.420-428.1982] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Chlamydia trachomatis LGV-434 was grown in HeLa 229 cells. Benzylpenicillin completely inhibited the formation of infectious elementary bodies (EBs) at a concentration of 19 pmol/ml or higher and produced abnormally large reticulate bodies (RBs) in the inclusions at 30 pmol/ml or higher. The possible targets for penicillin in C. trachomatis were three penicillin-binding proteins (PBPs) which were identified in the Sarkosyl-soluble fractions of both RBs and EBs. The apparent subunit molecular weights were 88,000 (PBP 1), 61,000 (BPB 2), and 36,000 (PBP 3). The 50% binding concentrations of [3H]penicillin for PBPs 1 to 3 in EBs and RBs were between 7 and 70 pmol/ml. Such high susceptibility to penicillin was shown by an organism that did not have detectable muramic acid (less than 0.02% by weight) in preparations of either whole cells or sodium dodecyl sulfate-insoluble residues.
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Caldwell HD, Kromhout J, Schachter J. Purification and partial characterization of the major outer membrane protein of Chlamydia trachomatis. Infect Immun 1981; 31:1161-76. [PMID: 7228399 PMCID: PMC351439 DOI: 10.1128/iai.31.3.1161-1176.1981] [Citation(s) in RCA: 839] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Elementary bodies (EB) of Chlamydia trachomatis serotypes C, E, and L2 were extrinsically radioiodinated, and whole-cell lysates of these serotypes were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Autoradiography of the polypeptide profiles identified a major surface protein with an apparent subunit molecular weight of 39,500 that was common to each C. trachomatis serotype. The abilities of nonionic (Triton X-100), dipolar ionic (Zwittergent TM-314), mild (sodium deoxycholate and sodium N-lauroyl sarcosine), and strongly anionic (SDS) detergents to extract this protein from intact EB of the L2 serotype were investigated by SDS-PAGE analysis of the soluble and insoluble fractions obtained after each detergent treatment. Only SDS readily extracted this protein from intact EB. Sarkosyl treatment selectively solubilized the majority of other EB proteins, leaving the 39,500-dalton protein associated with the Sarkosyl-insoluble fraction. Ultrastructural studies of the Sarkosyl-insoluble EB pellet showed it to consist of empty EB particles possessing an apparently intact outer membrane. No structural evidence for a peptidoglycan-like cell wall was found. Morphologically these chlamydial outer membrane complexes (COMC) resembled intact chlamydial EB outer membranes. The 39,500-dalton outer membrane protein was quantitatively extracted from COMC by treating them with 2% SDS at 60 degrees C. This protein accounted for 61% of the total COMC-associated protein, and its extraction resulted in a concomitant loss of the COMC membrane structure and morphology. The soluble extract obtained from SDS-treated COMC was adsorbed to a hydroxylapatite column and eluted with a linear sodium phosphate gradient. The 39,500-dalton protein was eluted from the column as a single peak at a phosphate concentration of approximately 0.3 M. The eluted protein was nearly homogeneous by SDS-PAGE and appeared free of contaminating carbohydrate, glycolipid, and nucleic acid. Hyperimmune mouse antiserum prepared against the 39,500-dalton protein from serotype L2 reacted with C. trachomatis serotypes Ba, E, D, K, L1, L2, and L3 by indirect immunofluorescence with EB but failed to react with serotypes A, B, C, F, G, H, I, and J, with the C. trachomatis mouse pneumonitis strain, or with the C. psittaci feline pneumonitis, guinea pig inclusion conjunctivitis, or 6BC strains. Thus, the 39,500-dalton major outer membrane protein is a serogroup antigen of C. trachomatis organisms.
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Storz J, Spears P. Chlamydiales: properties, cycle of development and effect on eukaryotic host cells. Curr Top Microbiol Immunol 1977; 76:167-214. [PMID: 334482 DOI: 10.1007/978-3-642-66653-7_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Curtiss R, Charamella LJ, Berg CM, Harris PE. Kinetic and genetic analyses of D-cycloserine inhibition and resistance in Escherichia coli. J Bacteriol 1965; 90:1238-50. [PMID: 5321479 PMCID: PMC315808 DOI: 10.1128/jb.90.5.1238-1250.1965] [Citation(s) in RCA: 100] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Curtiss, Roy, III (Oak Ridge National Laboratory, Oak Ridge, Tenn.), Leigh J. Charamella, Claire M. Berg, and Paula E. Harris. Kinetic and genetic analyses of d-cycloserine inhibition and resistance in Escherichia coli. J. Bacteriol. 90:1238-1250.1965.-Wild-type cells of Escherichia coli growing at 37 C in mineral salts-glucose medium with vigorous aeration were lysed at maximal exponential rates by 10(-4) to 10(-2)md-cycloserine. At concentrations above 2 x 10(-2)m, d-cycloserine was bacteriostatic. Low levels of d-cycloserine (10(-5)m) and pencillin G (10 units per ml) interacted synergistically to cause a rapid exponential rate of lysis. Spontaneous mutations to d-cycloserine resistance occurred in discrete steps at frequencies of 10(-6) to 10(-7) for each step. First-, second-, and third-step d-cycloserine-resistant mutants were lysed at maximal exponential rates by d-cycloserine concentrations of 10(-3), 3 x 10(-3), and 5 x 10(-3)m, respectively. d-Alanine, l-alanine, and dl-alanyl-dl-alanine reversed d-cycloserine-induced lysis, in that order of effectiveness. On the basis of these observations, a d-cycloserine-enrichment cycling technique was developed for isolation of auxotrophic mutants. d-Cycloserine at 2 x 10(-3)m was as efficient as penicillin G (1,000 units per ml) for mutant enrichment in E. coli and should be useful for isolation of mutants in penicillin-resistant microorganisms. Bacterial conjugation experiments indicated that all three mutations conferring d-cycloserine resistance were linked to the met(1) locus. Transduction experiments showed that the mutation conferring first-step resistance was at least 0.5 min away from the mutations conferring second- and third-step resistance. The latter two mutations possibly occurred in the same gene, since they were sometimes carried in the same transducing phage. Studies on expression of d-cycloserine resistance indicated that these mutations were neither dominant nor recessive to each other nor to the d-cycloserine-sensitivity allele. Each allelic state exerted its influence on the phenotype independently of the others. These results are discussed in terms of the known inhibition of alanine racemase and d-alanyl-d-alanine synthetase by d-cycloserine.
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