scholarly journals Combined Deletion of Four Francisella novicida Acid Phosphatases Attenuates Virulence and Macrophage Vacuolar Escape

2008 ◽  
Vol 76 (8) ◽  
pp. 3690-3699 ◽  
Author(s):  
Nrusingh P. Mohapatra ◽  
Shilpa Soni ◽  
Thomas J. Reilly ◽  
Jirong Liu ◽  
Karl E. Klose ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Etiologic Agent ◽  
Intracellular Pathogen ◽  
Acid Phosphatases ◽  
Francisella Novicida ◽  
Mutant Strains ◽  
Cell Cytosol ◽  
Host Cell Cytosol ◽  
Homologous Challenge ◽  
Dose Vaccine

ABSTRACT Francisella tularensis is a facultative intracellular pathogen and the etiologic agent of tularemia. It is capable of escape from macrophage phagosomes and replicates in the host cell cytosol. Bacterial acid phosphatases are thought to play a major role in the virulence and intracellular survival of a number of intracellular pathogens. The goal of this study was to delete the four primary acid phosphatases (Acps) from Francisella novicida and examine the interactions of mutant strains with macrophages, as well as the virulence of these strains in mice. We constructed F. novicida mutants with various combinations of acp deletions and showed that loss of the four Acps (AcpA, AcpB, AcpC, and histidine acid phosphatase [Hap]) in an F. novicida strain (ΔABCH) resulted in a 90% reduction in acid phosphatase activity. The ΔABCH mutant was defective for survival/growth within human and murine macrophage cell lines and was unable to escape from phagosome vacuoles. With accumulation of Acp deletions, a progressive loss of virulence in the mouse model was observed. The ΔABCH strain was dramatically attenuated and was an effective single-dose vaccine against homologous challenge. Furthermore, both acpA and hap were induced when the bacteria were within host macrophages. Thus, the Francisella acid phosphatases cumulatively play an important role in intracellular trafficking and virulence.

scholarly journals Listeriolysin O

2002 ◽  
Vol 156 (6) ◽  
pp. 943-946 ◽  
Author(s):  
Shaynoor Dramsi ◽  
Pascale Cossart
Keyword(s):  
Unique Feature ◽  
Single Amino Acid ◽  
Intracellular Pathogen ◽  
Listeriolysin O ◽  
Gram Positive Bacteria ◽  
Streptolysin O ◽  
Infected Cells ◽  
Cell Cytosol ◽  
Host Cell Cytosol ◽  
Optimal Ph

Cholesterol-dependent cytolysins (CDCs)**Abbreviations used in this paper: CDC, cholesterol-dependent cytolysin; LLO, listeriolysin O; PFO, perfringolysin O; SLO, streptolysin O. are produced by a large number of pathogenic gram–positive bacteria. A member of this family, listeriolysin O (LLO), is produced by the intracellular pathogen Listeria monocytogenes. A unique feature of LLO is its low optimal pH activity (∼6) which permits escape of the bacterium from the phagosome into the host cell cytosol without damaging the plasma membrane of the infected cell. In a recent study (Glomski et al., 2002, this issue), Portnoy's group has addressed the molecular mechanism underlying the pH sensitivity of LLO. Unexpectedly, a single amino acid substitution in LLO L461T results in a molecule more active at neutral pH and promoting premature permeabilization of the infected cells, leading to attenuated virulence. This finding highlights how subtle changes in proteins can be exploited by bacterial pathogens to establish and maintain the integrity of their specific niches.

scholarly journals Activation of theListeria monocytogenesVirulence Program by a Reducing Environment

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Jonathan L. Portman ◽  
Samuel B. Dubensky ◽  
Bret N. Peterson ◽  
Aaron T. Whiteley ◽  
Daniel A. Portnoy
Keyword(s):  
Gene Expression ◽  
Synthetic Medium ◽  
Virulence Gene ◽  
Intracellular Pathogen ◽  
Intracellular Pathogens ◽  
Virulence Gene Expression ◽  
Cell Cytosol ◽  
Host Cell Cytosol

ABSTRACTUpon entry into the host cell cytosol, the facultative intracellular pathogenListeria monocytogenescoordinates the expression of numerous essential virulence factors by allosteric binding of glutathione (GSH) to the Crp-Fnr family transcriptional regulator PrfA. Here, we report that robust virulence gene expression can be recapitulated by growing bacteria in a synthetic medium containing GSH or other chemical reducing agents. Bacteria grown under these conditions were 45-fold more virulent in an acute murine infection model and conferred greater immunity to a subsequent lethal challenge than bacteria grown in conventional media. During cultivationin vitro, PrfA activation was completely dependent on the intracellular levels of GSH, as a glutathione synthase mutant (ΔgshF) was activated by exogenous GSH but not reducing agents. PrfA activation was repressed in a synthetic medium supplemented with oligopeptides, but the repression was relieved by stimulation of the stringent response. These data suggest that cytosolicL. monocytogenesinterprets a combination of metabolic and redox cues as a signal to initiate robust virulence gene expressionin vivo.IMPORTANCEIntracellular pathogens are responsible for much of the worldwide morbidity and mortality from infectious diseases. These pathogens have evolved various strategies to proliferate within individual cells of the host and avoid the host immune response. Through cellular invasion or the use of specialized secretion machinery, all intracellular pathogens must access the host cell cytosol to establish their replicative niches. Determining how these pathogens sense and respond to the intracellular compartment to establish a successful infection is critical to our basic understanding of the pathogenesis of each organism and for the rational design of therapeutic interventions.Listeria monocytogenesis a model intracellular pathogen with robustin vitroandin vivoinfection models. Studies of the host-sensing and downstream signaling mechanisms evolved byL. monocytogenesoften describe themes of pathogenesis that are broadly applicable to less tractable pathogens. Here, we describe how bacteria use external redox states as a cue to activate virulence.

scholarly journals Acid Phosphatases Do Not Contribute to the Pathogenesis of Type A Francisella tularensis

2009 ◽  
Vol 78 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Robert Child ◽  
Tara D. Wehrly ◽  
Dedeke Rockx-Brouwer ◽  
David W. Dorward ◽  
Jean Celli
Keyword(s):  
Acid Phosphatase ◽  
Francisella Tularensis ◽  
Type A ◽  
Intracellular Pathogen ◽  
Acid Phosphatases ◽  
Intranasal Inoculation ◽  
Human Macrophages ◽  
Virulent Type ◽  
Schu S4 ◽  
Highly Virulent

ABSTRACT The intracellular pathogen Francisella tularensis is the causative agent of tularemia, a zoonosis that can affect humans with potentially lethal consequences. Essential to Francisella virulence is its ability to survive and proliferate within phagocytes through phagosomal escape and cytosolic replication. Francisella spp. encode a variety of acid phosphatases, whose roles in phagosomal escape and virulence have been documented yet remain controversial. Here we have examined in the highly virulent (type A) F. tularensis strain Schu S4 the pathogenic roles of three distinct acid phosphatases, AcpA, AcpB, and AcpC, that are most conserved between Francisella subspecies. Neither the deletion of acpA nor the combination of acpA, acpB, and acpC deletions affected the phagosomal escape or cytosolic growth of Schu S4 in murine and human macrophages, despite decreases in acid phosphatase activities by as much as 95%. Furthermore, none of these mutants were affected in their ability to cause lethality in mice upon intranasal inoculation. Hence, the acid phosphatases AcpA, AcpB, and AcpC do not contribute to intracellular pathogenesis and do not play a major role in the virulence of type A Francisella strains.

scholarly journals The Acid Phosphatase AcpA Is SecretedIn Vitroand in Macrophages by Francisella spp.

2011 ◽  
Vol 80 (3) ◽  
pp. 1088-1097 ◽  
Author(s):  
Shipan Dai ◽  
Nrusingh P. Mohapatra ◽  
Larry S. Schlesinger ◽  
John S. Gunn
Keyword(s):  
Acid Phosphatase ◽  
Respiratory Burst ◽  
Culture Supernatant ◽  
Intracellular Pathogen ◽  
Acid Phosphatases ◽  
Macrophage Infection ◽  
Content Type ◽  
Schu S4 ◽  
Highly Virulent

Francisella tularensisis a remarkably infectious facultative intracellular pathogen that causes the zoonotic disease tularemia. Essential to the pathogenesis ofF. tularensisis its ability to escape the destructive phagosomal environment and inhibit the host cell respiratory burst.F. tularensissubspecies encode a series of acid phosphatases, which have been reported to play important roles inFrancisellaphagosomal escape, inhibition of the respiratory burst, and intracellular survival. However, rigorous demonstration of acid phosphatase secretion by intracellularFrancisellahas not been shown. Here, we demonstrate that AcpA, which contributes most of theF. tularensisacid phosphatase activity, is secreted into the culture supernatantin vitrobyF. novicidaandF. tularensissubsp.holarcticaLVS. In addition, bothF. novicidaand the highly virulentF. tularensissubsp.tularensisSchu S4 strain are able to secrete and also translocate AcpA into the host macrophage cytosol. This is the first evidence of acid phosphatase translocation during macrophage infection, and this knowledge will greatly enhance our understanding of the functions of these enzymes inFrancisellapathogenesis.

The Demonstration of Human Prostatic Acid Phosphatase (Pap) With Phosphorylcholine

1976 ◽  
Vol 34 ◽  
pp. 88-89
Author(s):  
José A. Serrano ◽  
Hannah L. Wasserkrug ◽  
Anna A. Serrano ◽  
Arnold M. Seligman
Keyword(s):  
Acid Phosphatase ◽  
Prostate Gland ◽  
Prostatic Acid Phosphatase ◽  
Human Prostate ◽  
Rat Tissues ◽  
Specific Substrate ◽  
Acid Phosphatases ◽  
Lysosomal Acid ◽  
Cacodylate Buffer

As previously reported (1, 2) phosphorylcholine (PC) is a specific substrate for prostatatic acid phosphatase (PAP) as opposed to other acid phosphatases, e.g., lysosomal acid phosphatase. The specificity of PC for PAP is due to the pentavalent nitrogen in PC, a feature that renders PC resistant to hydrolysis by all other acid phosphatases. Detailed comparative cytochemical results in rat tissues are in press. This report deals with ultracytochemical results applying the method to normal and pathological human prostate gland.Fresh human prostate was obtained from 7 patients having transurethral resections or radical prostatectomies. The tissue was fixed in 3% glutaraldehyde- 0.1 M cacodylate buffer (pH 7.4) for 15 min, sectioned at 50 μm on a Sorvall TC-2 tissue sectioner, refixed for a total of 2 hr, and rinsed overnight in 0.1 M cacodylate buffer (pH 7.4)-7.5% sucrose.

In vitro translation of human prostatic acid phosphatase mRNA and processing of the translation products by microsomal membranes and endoglycosidase H

1987 ◽  
Vol 65 (10) ◽  
pp. 921-924 ◽  
Author(s):  
Gilles Paradis ◽  
Jean Y. Dubé ◽  
Pierre Chapdelaine ◽  
Roland R. Tremblay
Keyword(s):  
Acid Phosphatase ◽  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Prostatic Acid Phosphatase ◽  
In Vitro Translation ◽  
Acid Phosphatases ◽  
Major Band ◽  
Microsomal Membranes ◽  
Endoglycosidase H

Poly(A)+ RNA was isolated from human prostatic tissue and translated in vitro in a rabbit reticulocyte lysate translation assay. Acid phosphatase labeled with [35S]methionine was immunoprecipitated with an antibody against seminal plasma acid phosphatase. Two-dimensional polyacrylamide gel electrophoresis of the immunoprecipitate, followed by fluorography, revealed the presence of two spots (one major and one minor), both having a molecular mass of 43 kilodaltons (kDa) and an isoelectric point higher than mature acid phosphatase. Addition of canine pancreatic membranes to the translation assay resulted in the formation of four immunoprecipitable spots with molecular masses ranging from 43 to 49 kDa on one-dimensional gels. These spots probably represent acid phosphatases containing one to four core sugar groups, since after the addition of endoglycosidase H the molecular mass heterogeneity was abolished and we observed only one major band with a molecular mass (41 kDa) slightly lower than the ones of the primary translation product. These results suggest that human prostatic acid phosphatases are synthesized as two 43-kDa preproteins, which are further processed to 41-kDa proteins by removal of their signal peptide. Heterogeneity of the native protein arises mostly from glycosylation at four sites and not from differences in the amino acid sequence of the various forms.

Parasitophorous vacuoles of Leishmania mexicana acquire macromolecules from the host cell cytosol via two independent routes

1999 ◽  
Vol 112 (5) ◽  
pp. 681-693
Author(s):  
U.E. Schaible ◽  
P.H. Schlesinger ◽  
T.H. Steinberg ◽  
W.F. Mangel ◽  
T. Kobayashi ◽  
...  
Keyword(s):  
Host Cell ◽  
Lucifer Yellow ◽  
Cysteine Proteinase ◽  
Organic Anion ◽  
Organic Anion Transporter ◽  
Anion Transporter ◽  
Infected Cells ◽  
Lysobisphosphatidic Acid ◽  
Cell Cytosol ◽  
Host Cell Cytosol

The intracellular parasite Leishmania survives and proliferates in host macrophages. In this study we show that parasitophorous vacuoles of L. mexicana gain access to cytosolic material via two different routes. (1) Small anionic molecules such as Lucifer Yellow are rapidly transported into the vacuoles by an active transport mechanism that is sensitive to inhibitors of the host cell's organic anion transporter. (2) Larger molecules such as fluorescent dextrans introduced into the host cell cytosol are also delivered to parasitophorous vacuoles. This transport is slower and sensitive to modulators of autophagy. Infected macrophages were examined by two novel assays to visualize and quantify this process. Immunoelectron microscopy of cells loaded with digoxigenin-dextran revealed label in multivesicular endosomes, which appeared to fuse with parasitophorous vacuoles. The inner membranes of the multivesicular vesicles label strongly with antibodies against lysobisphosphatidic acid, suggesting that they represent a point of confluence between the endosomal and autophagosomal pathways. Although the rate of autophagous transfer was comparable in infected and uninfected cells, infected cells retained hydrolyzed cysteine proteinase substrate to a greater degree. These data suggest that L. mexicana-containing vacuoles have access to potential nutrients in the host cell cytosol via at least two independent mechanisms.

scholarly journals Recent advances in understanding Listeria monocytogenes infection: the importance of subcellular and physiological context

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1126 ◽  
Author(s):  
Daryl J. V. David ◽  
Pascale Cossart
Keyword(s):  
Listeria Monocytogenes ◽  
Gut Microbiota ◽  
Bacterial Pathogen ◽  
Cell Types ◽  
Infection Process ◽  
Foodborne Disease ◽  
Listeria Monocytogenes Infection ◽  
Cell Cytosol ◽  
Critical Components ◽  
Host Cell Cytosol

The bacterial pathogen Listeria monocytogenes (Lm) is the causative agent of listeriosis, a rare but fatal foodborne disease. During infection, Lm can traverse several host barriers and enter the cytosol of a variety of cell types. Thus, consideration of the extracellular and intracellular niches of Lm is critical for understanding the infection process. Here, we review advances in our understanding of Lm infection and highlight how the interactions between the host and the pathogen are context dependent. We discuss discoveries of how Lm senses entry into the host cell cytosol. We present findings concerning how the nature of the various cytoskeleton components subverted by Lm changes depending on both the stage of infection and the subcellular context. We present discoveries of critical components required for Lm traversal of physiological barriers. Interactions between the host gut microbiota and Lm will be briefly discussed. Finally, the importance of Lm biodiversity and post-genomics approaches as a promising way to discover novel virulence factors will be highlighted.

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