Influence of Cysteine Deprivation on Chlamydial Differentiation from Reproductive to Infective Life-cycle Forms

Allan, I.; Hatch, Thomas P.; Pearce, J. H.

doi:10.1099/00221287-131-12-3171

Cited by 19 publications

(18 citation statements)

References 15 publications

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“…Developmental form-specific transcription in CIP-1 was confirmed by microarray analysis. Overall, C. trachomatis de novo protein synthesis in CIP-1 shows a substantial improvement over previously described media (6,10,27) and will facilitate analysis of chlamydial physiology and metabolism in the absence of the background of a host cell.…”

Section: Discussionmentioning

confidence: 91%

Developmental stage-specific metabolic and transcriptional activity of Chlamydia trachomatis in an axenic medium

Omsland¹,

Sager²,

Nair

et al. 2012

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

136

149

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Chlamydia trachomatis is among the most clinically significant human pathogens, yet their obligate intracellular nature places severe restrictions upon research. Chlamydiae undergo a biphasic developmental cycle characterized by an infectious cell type known as an elementary body (EB) and an intracellular replicative form called a reticulate body (RB). EBs have historically been described as metabolically dormant. A cell-free (axenic) culture system was developed, which showed high levels of metabolic and biosynthetic activity from both EBs and RBs, although the requirements differed for each. EBs preferentially used glucose-6-phosphate as an energy source, whereas RBs required ATP. Both developmental forms showed increased activity when incubated under microaerobic conditions. Incorporation of isotopically labeled amino acids into proteins from both developmental forms indicated unique expression profiles, which were confirmed by genome-wide transcriptional analysis. The described axenic culture system will greatly enhance biochemical and physiological analyses of chlamydiae.

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Section: Discussionmentioning

confidence: 91%

Developmental stage-specific metabolic and transcriptional activity of Chlamydia trachomatis in an axenic medium

Omsland¹,

Sager²,

Nair

et al. 2012

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

136

149

View full text Add to dashboard Cite

show abstract

“…CCL2), and the stocks were prepared as described previously (20). Briefly, HeLa cells grown in either 24-well plates with coverslips or tissue flasks containing Dulbecco's modified essential medium (DMEM) (Gibco BRL, Rockville, MD) with 10% fetal calf serum (FCS; Gibco BRL) at 37°C in an incubator supplied with 5% CO 2 were inoculated with C. trachomatis stock organisms. The infected cultures were harvested at different time points postinfection for either organism purification and outer membrane complex (OMC) preparation or Western blot analyses as described below.…”

Section: Methodsmentioning

confidence: 99%

Characterization of Pgp3, aChlamydia trachomatisPlasmid-Encoded Immunodominant Antigen

Chen¹,

Lei²,

Lu³

et al. 2010

J Bacteriol

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Human antibody recognition of Chlamydia trachomatis plasmid-encoded Pgp3 protein is dependent on the native conformation of Pgp3. The structural basis for the conformation dependence and the function of Pgp3 remain unknown. Here, we report that Pgp3 trimerization is required for the recognition of Pgp3 by human antibodies. In a native polyacrylamide gel, Pgp3 purified from a bacterial expression system migrated as stable trimers that were dissociated into monomers only by treatment with urea or sodium dodecyl sulfate (SDS) but not nonionic detergents. Human antibodies recognized trimeric but not monomeric Pgp3, suggesting that Pgp3 is presented to the human immune system as trimers during C. trachomatis infection. The endogenous Pgp3 secreted into the chlamydial outer membrane complex or host cell cytosol is always trimerized. Intact Pgp3 trimers were eluted from the outer membrane complex by a combination of nonionic detergents with reducing agents but not by the presence of either alone. These observations have provided important information for further understanding the role of Pgp3 in chlamydial pathogenesis and potentially optimizing Pgp3 as a subunit vaccine candidate antigen.

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“…Indeed, in vitro evidence demonstrates that limiting availability of metabolites such as amino acids, glucose, and iron induced the production of aberrant chlamydial forms with reduced infectivity (1,2,4,13,14,23,52). However, increasing levels of the soluble metabolites by reintroduction of metabolites into starved cultures or by adding the eukaryotic protein synthesis repressor cycloheximide into infected cell cultures starved or grown under standard conditions recovers or improves the growth and the infectivity of chlamydiae (1,4,24,40,52).…”

mentioning

confidence: 99%

Interaction ofChlamydia trachomatisSerovar L2 with the Host Autophagic Pathway

Al-Younes¹,

Brinkmann

Meyer³

2004

Infect Immun

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Chlamydiae are obligate intracellular pathogens that replicate within a membrane-bound compartment (the inclusion) and are associated with important human diseases, such as trachoma, pneumonia, and atherosclerosis. We have examined the interaction of the host autophagic pathway with Chlamydia trachomatis serovar L2 by using the specific autophagosomal stain monodansylcadaverine, antibodies to autophagosome-associated markers, and traditionally used autophagic inhibitors, particularly 3-methyladenine and amino acids. Chlamydial inclusions did not sequester monodansylcadaverine, suggesting absence of fusion with autophagosomes. Interestingly, exposure of cultures infected for 19 h to 3-methyladenine or single amino acids until the end of infection (44 h) caused various degrees of abnormalities in the inclusion maturation and in the progeny infectivity. Incubation of host cells with chemicals throughout the entire period of infection modulated the growth of Chlamydia even more dramatically. Remarkably, autophagosomal markers MAP-LC3 and calreticulin were redistributed to the inclusion of Chlamydia, a process that appears to be sensitive to 3-methyladenine and some amino acids. The present data indicate the lack of autophagosomal fusion with the inclusion because it was devoid of monodansylcadaverine and no distinct rim of autophagosomal protein-specific staining around the inclusion could be observed. However, high sensitivity of Chlamydia to conditions that could inhibit host autophagic pathway and the close association of MAP-LC3 and calreticulin with the inclusion membrane still suggest a potential role of host autophagy in the pathogenesis of Chlamydia.

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Influence of Cysteine Deprivation on Chlamydial Differentiation from Reproductive to Infective Life-cycle Forms

Cited by 19 publications

References 15 publications

Developmental stage-specific metabolic and transcriptional activity of Chlamydia trachomatis in an axenic medium

Developmental stage-specific metabolic and transcriptional activity of Chlamydia trachomatis in an axenic medium

Characterization of Pgp3, aChlamydia trachomatisPlasmid-Encoded Immunodominant Antigen

Interaction ofChlamydia trachomatisSerovar L2 with the Host Autophagic Pathway

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