scholarly journals Single Cell Cryo-Soft X-ray Tomography Shows That Each Chlamydia Trachomatis Inclusion Is a Unique Community of Bacteria

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 842
Author(s):  
Patrick Phillips ◽  
James M. Parkhurst ◽  
Ilias Kounatidis ◽  
Chidinma Okolo ◽  
Thomas M. Fish ◽  
...  

Chlamydiae are strict intracellular pathogens residing within a specialised membrane-bound compartment called the inclusion. Therefore, each infected cell can, be considered as a single entity where bacteria form a community within the inclusion. It remains unclear as to how the population of bacteria within the inclusion influences individual bacterium. The life cycle of Chlamydia involves transitioning between the invasive elementary bodies (EBs) and replicative reticulate bodies (RBs). We have used cryo-soft X-ray tomography to observe individual inclusions, an approach that combines 40 nm spatial resolution and large volume imaging (up to 16 µm). Using semi-automated segmentation pipeline, we considered each inclusion as an individual bacterial niche. Within each inclusion, we identifyed and classified different forms of the bacteria and confirmed the recent finding that RBs have a variety of volumes (small, large and abnormal). We demonstrate that the proportions of these different RB forms depend on the bacterial concentration in the inclusion. We conclude that each inclusion operates as an autonomous community that influences the characteristics of individual bacteria within the inclusion.

2014 ◽  
Author(s):  
Joshua K. Y. Swee ◽  
Clare Sheridan ◽  
Elza de Bruin ◽  
Julian Downward ◽  
Francois Lassailly ◽  
...  

Although, as is well known, the ultra-microscopic viruses are invisible in histological preparations, yet characteristic bodies occur within certain of the cells of animals infected with such organisms. The origin and nature of these so-called “virus bodies” has been the subject of much controversy. By some they have been regarded as the actual parasite, or at least as phases in its life cycle. To von Prowazek they were dual in character consisting of microorganisms embedded in material produced by the reaction of the cytoplasm of the infected cell. Still other observers regarded such bodies as products of cellular disintegration. In a former paper (Findlay and Ludford (1926)) we have referred to the various views held by writers in this field and have made a survey of the literature of the subject in the form of a pictographic review. We shall, therefore, only mention previous work in this field, in so far as it directly concerns our personal observations. A conspicuous fault of much of the earlier work has been the unsatisfactory histological technique employed, especially the nature of the fixative. The earlier cytological work was carried out with fixatives, which although satisfactory for the subsequent demonstration of nuclear structures were very destructive to the cytoplasm. This is particularly unfortunate since most of the virus bodies occur in the ground cytoplasm of cells. We have endeavoured to rectify this source of error in our work by employing fixatives, which have been proved to fix the cells in such a manner as to give an appearance as nearly as possible identical with their structure, as seen in the living cells.


2021 ◽  
Vol 12 (2) ◽  
pp. 136
Author(s):  
Sándor Kónya ◽  
TR Sai Natarajan ◽  
Hassan Allouch ◽  
KaisAbu Nahleh ◽  
OmneyaYakout Dogheim ◽  
...  

2015 ◽  
Vol 46 ◽  
pp. 1468-1475 ◽  
Author(s):  
Ajay K. Mandava ◽  
Emma E. Regentova ◽  
Markus Berli
Keyword(s):  

2007 ◽  
Author(s):  
Suguru Kawajiri ◽  
Xiangrong Zhou ◽  
Xuejin Zhang ◽  
Takeshi Hara ◽  
Hiroshi Fujita ◽  
...  

2017 ◽  
Vol 85 (5) ◽  
Author(s):  
Ashley M. Sherrid ◽  
Kevin Hybiske

ABSTRACT The strategies utilized by pathogens to exit host cells are an area of pathogenesis which has received surprisingly little attention, considering the necessity of this step for infections to propagate. Even less is known about how exit through these pathways affects downstream host-pathogen interactions and the generation of an immune response. Chlamydia trachomatis exits host epithelial cells through two equally active mechanisms: lysis and extrusion. Studies have characterized the outcome of interactions between host innate immune cells, such as dendritic cells and macrophages, and free, extracellular Chlamydia bacteria, such as those resulting from lysis. Exit via extrusion generates a distinct, host-membrane-bound compartment of Chlamydia separate from the original infected cell. In this study, we assessed the effect of containment within extrusions upon the interaction between Chlamydia and host dendritic cells. Extrusion dramatically affected the outcome of Chlamydia-dendritic cell interactions for both the bacterium and the host cell. Dendritic cells rapidly underwent apoptosis in response to engulfment of an extrusion, while uptake of an equivalent dose of free Chlamydia had no such effect. Containment within an extrusion also prolonged bacterial survival within dendritic cells and altered the initial innate immune signaling by the dendritic cell.


2018 ◽  
Vol 115 (23) ◽  
pp. 5950-5955 ◽  
Author(s):  
Bastien Casu ◽  
Charline Mary ◽  
Aleksandr Sverzhinsky ◽  
Aurélien Fouillen ◽  
Antonio Nanci ◽  
...  

Type IV secretion systems (T4SSs) are multiprotein assemblies that translocate macromolecules across the cell envelope of bacteria. X-ray crystallographic and electron microscopy (EM) analyses have increasingly provided structural information on individual T4SS components and on the entire complex. As of now, relatively little information has been available on the exact localization of the inner membrane-bound T4SS components, notably the mostly periplasmic VirB8 protein and the very hydrophobic VirB6 protein. We show here that the membrane-bound, full-length version of the VirB8 homolog TraE from the plasmid pKM101 secretion system forms a high-molecular-mass complex that is distinct from the previously characterized periplasmic portion of the protein that forms dimers. Full-length TraE was extracted from the membranes with detergents, and analysis by size-exclusion chromatography, cross-linking, and size exclusion chromatography (SEC) multiangle light scattering (MALS) shows that it forms a high-molecular-mass complex. EM and small-angle X-ray scattering (SAXS) analysis demonstrate that full-length TraE forms a hexameric complex with a central pore. We also overproduced and purified the VirB6 homolog TraD and show by cross-linking, SEC, and EM that it binds to TraE. Our results suggest that TraE and TraD interact at the substrate translocation pore of the secretion system.


2020 ◽  
Vol 118 (3) ◽  
pp. 503a
Author(s):  
Dennis J. Michalak ◽  
Ellen Lorimer ◽  
Bethany Unger ◽  
Carol L. Williams ◽  
Frank Heinrich ◽  
...  

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