Document Detail


HeLa cells as a model to study the invasiveness and biology of Legionella pneumophila.
MedLine Citation:
PMID:  9699298     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
HeLa cells were established as a model system to study the invasiveness and biology of Legionella pneumophila. In this model, invasion could be distinguished from adherence; virulent strains of L. pneumophila were adherent and invasive, whereas nonvirulent strains were adherent but poorly invasive. Invasion was rapid and did not require de novo bacterial protein synthesis, suggesting that the invasion factor is constitutively expressed by virulent strains. Entry into HeLa cells required actin polymerization and an intact microtubule cytoskeleton and was only moderately inhibited by the presence of 100 mM glucose or galactose. Intracellular replication of virulent L. pneumophila took place in ribosome-studded complex endosomes and led to the formation of free bacteria-laden vesicles presumably released from lysed HeLa cells. These free vesicles (referred to as mature vesicles) were isolated in continuous density gradients of Percoll. The bacteria contained in the isolated mature vesicles had a unique envelope structure and were highly adherent to HeLa cells, characteristics that correlated with a bright red appearance after the Giménez stain (Giménez positive). Plate-grown legionellae and replicating legionellae, harboured in complex endosomes, displayed a typical Gram-negative envelope and stained green after the Giménez stain (Giménez negative). Chronically infected cultures of HeLa cells were also established that may be a useful tool for studying long-term interactions between virulent L. pneumophila and mammalian cells. HeLa cells constitute a valuable model system that offers unique opportunities to study parasite-directed endocytosis, as well as stage specific-parasite interactions.
Authors:
R A Garduño; F D Quinn; P S Hoffman
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Canadian journal of microbiology     Volume:  44     ISSN:  0008-4166     ISO Abbreviation:  Can. J. Microbiol.     Publication Date:  1998 May 
Date Detail:
Created Date:  1998-09-17     Completed Date:  1998-09-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372707     Medline TA:  Can J Microbiol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  430-40     Citation Subset:  IM    
Affiliation:
Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
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MeSH Terms
Descriptor/Qualifier:
Bacterial Adhesion
Cell Fractionation
Colchicine / pharmacology
Colony Count, Microbial
Cytochalasin D / pharmacology
Cytoskeleton / physiology
Galactose / pharmacology
Glucose / pharmacology
Hela Cells / microbiology*,  ultrastructure
Humans
Legionella pneumophila / growth & development*,  pathogenicity*,  ultrastructure
Microscopy, Electron
Nocodazole / pharmacology
Organelles / ultrastructure
Virulence
Chemical
Reg. No./Substance:
22144-77-0/Cytochalasin D; 26566-61-0/Galactose; 31430-18-9/Nocodazole; 50-99-7/Glucose; 64-86-8/Colchicine

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