Ultrastructural analysis of chlamydial antigen-containing vesicles everting from the Chlamydia trachomatis inclusion

Giles, David K.; Whittimore, Judy D.; LaRue, Richard W.; Raulston, Jane E.; Wyrick, Priscilla B.

doi:10.1016/j.micinf.2006.01.018

Cited by 34 publications

(44 citation statements)

References 74 publications

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“…Live microscopy of C. trachomatis-infected cells in the presence of LpxC inhibitors over a 20-h time period suggested that replication and inclusion expansion was indistinguishable from DMSO-treated controls (Movie S1). Interestingly, as previously reported (23,24), antichlamydial LOS antibodies detected immunoreactive material in the host cytoplasm of infected and adjacent uninfected cells. There has been controversy as to whether LPS shedding in the cytosol of the host cell was an artifact of fixation.…”

Section: Anti-infectivessupporting

confidence: 84%

Lipooligosaccharide is required for the generation of infectious elementary bodies in Chlamydia trachomatis

Nguyen

Cunningham

Liang

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Lipopolysaccharides (LPS) and lipooligosaccharides (LOS) are the main lipid components of bacterial outer membranes and are essential for cell viability in most Gram-negative bacteria. Here we show that small molecule inhibitors of LpxC [UDP-3- O -( R -3-hydroxymyristoyl)-GlcNAc deacetylase], the enzyme that catalyzes the first committed step in the biosynthesis of lipid A, block the synthesis of LOS in the obligate intracellular bacterial pathogen Chlamydia trachomatis . In the absence of LOS, Chlamydia remains viable and establishes a pathogenic vacuole (“inclusion”) that supports robust bacterial replication. However, bacteria grown under these conditions were no longer infectious. In the presence of LpxC inhibitors, replicative reticulate bodies accumulated in enlarged inclusions but failed to express selected late-stage proteins and transition to elementary bodies, a Chlamydia developmental form that is required for invasion of mammalian cells. These findings suggest the presence of an outer membrane quality control system that regulates Chlamydia developmental transition to infectious elementary bodies and highlights the potential application of LpxC inhibitors as unique class of antichlamydial agents.

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Section: Anti-infectivessupporting

confidence: 84%

Lipooligosaccharide is required for the generation of infectious elementary bodies in Chlamydia trachomatis

Nguyen

Cunningham

Liang

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Confluent RK-13 monolayers grown in 75-cm 2 flasks were infected with E. cuniculi or Encephalitozoon intestinalis spores and were maintained until numerous infected cells were visible by light microscopy. Heavily infected monolayers were prepared for immunoelectron microscopy (IEM) as previously described (9). Briefly, the infected monolayers were fixed with 2% paraformaldehyde and 0.05% glutaraldehyde, scraped from the flask, and enrobed in 3% SeaKem agar.…”

Section: Methodsmentioning

confidence: 99%

EnP1, a Microsporidian Spore Wall Protein That Enables Spores To Adhere to and Infect Host Cells In Vitro

et al. 2007

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Microsporidia are spore-forming fungal pathogens that require the intracellular environment of host cells for propagation. We have shown that spores of the genus Encephalitozoon adhere to host cell surface glycosaminoglycans (GAGs) in vitro and that this adherence serves to modulate the infection process. In this study, a spore wall protein (EnP1; Encephalitozoon cuniculi ECU01_0820) from E. cuniculi and Encephalitozoon intestinalis is found to interact with the host cell surface. Analysis of the amino acid sequence reveals multiple heparin-binding motifs, which are known to interact with extracellular matrices. Both recombinant EnP1 protein and purified EnP1 antibody inhibit spore adherence, resulting in decreased host cell infection. Furthermore, when the N-terminal heparin-binding motif is deleted by site-directed mutagenesis, inhibition of adherence is ablated. Our transmission immunoelectron microscopy reveals that EnP1 is embedded in the microsporidial endospore and exospore and is found in high abundance in the polar sac/anchoring disk region, an area from which the everting polar tube is released. Finally, by using a host cell binding assay, EnP1 is shown to bind host cell surfaces but not to those that lack surface GAGs. Collectively, these data show that given its expression in both the endospore and the exospore, EnP1 is a microsporidian cell wall protein that may function both in a structural capacity and in modulating in vitro host cell adherence and infection.

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“…The predictive amino acid sequences of C. trachomatis serovar E Hsp60-1, Hsp60-2, and Hsp60-3 were aligned using the EditSeq and MegAlign software from DNAStar, Inc. (Madison, WI). Peptides that were 17 to 21 residues long, described by Giles et al (21), were commercially synthesized, the purity was assessed by analytical high-pressure liquid chromatography and mass spectroscopy, and each peptide was subsequently used to immunize two female New Zealand White rabbits (Sigma-Genosys, The Woodlands, TX). The results of enzyme-linked immunosorbent assays were provided by the manufacturer to ensure reactivity.…”

Section: Methodsmentioning

confidence: 99%

“…Samples of C. trachomatis-infected polarized HEC-1B cells at 36 hpi were exposed to 500 M Desferal for 30 min and 1 and 2 h; mock-exposed samples were used as controls. Each sample was immediately washed, fixed, processed, and embedded in Epon-araldite and Lowicryl (Polysciences, Inc.) for high-contrast electron microscopy and immunoelectron microscopy, respectively, as described by Giles et al (21).…”

Section: Methodsmentioning

confidence: 99%

Chlamydial Hsp60-2 Is Iron Responsive in Chlamydia trachomatis Serovar E-Infected Human Endometrial Epithelial Cells In Vitro

LaRue¹,

Dill²,

Giles³

et al. 2007

Infect Immun

Self Cite

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Chlamydial 60-kDa heat shock proteins (cHsp60s) are known to play a prominent role in the immunopathogenesis of disease. It is also known that several stress-inducing growth conditions, such as heat, iron deprivation, or exposure to gamma interferon, result in the development of persistent chlamydial forms that often exhibit enhanced expression of cHsp60. We have shown previously that the expression of cHsp60 is greatly enhanced in Chlamydia trachomatis serovar E propagated in an iron-deficient medium. The objective of this work was to determine which single cHsp60 or combination of the three cHsp60 homologs encoded by this organism responds to iron limitation. Using monospecific polyclonal peptide antisera that recognize only cHsp60-1, cHsp60-2, or cHsp60-3, we found that expression of cHsp60-2 is responsive to iron deprivation. Overall, our studies suggest that the expression of cHsp60 homologs differs among the mechanisms currently known to induce persistence.

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Ultrastructural analysis of chlamydial antigen-containing vesicles everting from the Chlamydia trachomatis inclusion

Cited by 34 publications

References 74 publications

Lipooligosaccharide is required for the generation of infectious elementary bodies in Chlamydia trachomatis

Lipooligosaccharide is required for the generation of infectious elementary bodies in Chlamydia trachomatis

EnP1, a Microsporidian Spore Wall Protein That Enables Spores To Adhere to and Infect Host Cells In Vitro

Chlamydial Hsp60-2 Is Iron Responsive in Chlamydia trachomatis Serovar E-Infected Human Endometrial Epithelial Cells In Vitro

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