title: Differential Translocation of Host Cellular Materials into the Chlamydia trachomatis Inclusion Lumen during Chemical Fixation.
abstract: Chlamydia trachomatis manipulates host cellular pathways to ensure its proliferation and survival. Translocation of host materials into the pathogenic vacuole (termed 'inclusion') may facilitate nutrient acquisition and various organelles have been observed within the inclusion, including lipid droplets, peroxisomes, multivesicular body components, and membranes of the endoplasmic reticulum (ER). However, few of these processes have been documented in living cells. Here, we survey the localization of a broad panel of subcellular elements and find ER, mitochondria, and inclusion membranes within the inclusion lumen of fixed cells. However, we see little evidence of intraluminal localization of these organelles in live inclusions. Using time-lapse video microscopy we document ER marker translocation into the inclusion lumen during chemical fixation. These intra-inclusion ER elements resist a variety of post-fixation manipulations and are detectable via immunofluorescence microscopy. We speculate that the localization of a subset of organelles may be exaggerated during fixation. Finally, we find similar structures within the pathogenic vacuole of Coxiella burnetti infected cells, suggesting that fixation-induced translocation of cellular materials may occur into the vacuole of a range of intracellular pathogens.
authors.affiliation: Department of Molecular Genetics and Microbiology and Center for the Genomics of Microbial Systems, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Marcela
authors.initials: M
authors.lastname: Kokes
authors.affiliation: Department of Molecular Genetics and Microbiology and Center for the Genomics of Microbial Systems, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Raphael H
authors.initials: RH
authors.lastname: Valdivia
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport; D002692:Chlamydia trachomatis / Q000378:metabolism* / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000378:metabolism; D057146:Multivesicular Bodies / Q000378:metabolism* / Q000648:ultrastructure; D059008:Time-Lapse Imaging; D016707:Tissue Fixation / Q000379:methods*; D014617:Vacuoles / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins