DOCSLIB.ORG

Mutational Analysis of the Group a Streptococcal Operon Encoding Streptolysin S and Its Virulence Role in Invasive Infection

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mutational Analysis of the Group a Streptococcal Operon Encoding Streptolysin S and Its Virulence Role in Invasive Infection Blackwell Science, LtdOxford, UKMMIMolecular Microbiology0950-382XBlackwell Publishing Ltd, 2005? 2005563681695Original ArticleSLS operon and invasive GAS infectionV. Datta et al. Molecular Microbiology (2005) 56(3), 681–695 doi:10.1111/j.1365-2958.2005.04583.x Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection Vivekanand Datta,1 Sandra M. Myskowski,1 Introduction Laura A. Kwinn,1 Daniel N. Chiem,1 Nissi Varki,2 Group A Streptococcus (GAS) is a leading human patho- Rita G. Kansal,3 Malak Kotb3 and Victor Nizet1* gen causing common infections such as pharyngitis 1Department of Pediatrics, Division of Infectious Diseases (‘strep throat’) and impetigo (Cunningham, 2000; Bisno and 2Department of Medicine, Glycobiology Research et al., 2003). During the last three decades, a resur- and Training Center, University of California, San Diego, gence of severe invasive GAS infection has been docu- La Jolla, CA, USA. mented worldwide (Efstratiou, 2000). Prominent among 3Veterans Affairs Medical Center, Research Service, invasive GAS syndromes are the destructive soft tissue Memphis TN, USA. infection necrotizing fasciitis (NF) and the multisystem disorder of streptococcal toxic shock syndrome (STSS), Summary each carrying significant risk of morbidity and mortality even with aggressive medical therapy (Stevens, 1999; The pathogen group A Streptococcus (GAS) pro- Sharkawy et al., 2002). While GAS strains of many M duces a wide spectrum of infections including necro- protein (emm) genotypes are capable of producing sig- tizing fasciitis (NF). Streptolysin S (SLS) produces the nificant disease, strains representing one globally dis- hallmark b-haemolytic phenotype produced by GAS. seminated clonal M1T1 GAS strain have persisted for The nine-gene GAS locus (sagA–sagI) resembling a over 20 years as the single most prevalent isolate from bacteriocin biosynthetic operon is necessary and invasive GAS infections (Cockerill et al., 1997; Cleary sufficient for SLS production. Using precise, in- et al., 1998; Murono et al., 1999; Chatellier et al., 2000), frame allelic exchange mutagenesis and single-gene including all nine surveillance centres of the United complementation, we show sagA, sagB, sagC, sagD, States Centers for Disease Control Emerging Infections sagE, sagF and sagG are each individually required Program Network in 2002 (http://www.cdc.gov/ncidod/ for SLS production, and that sagE may further serve dbmd/abcs). an immunity function. Limited site-directed muta- A hallmark phenotypic feature of GAS is the distinct genesis of specific amino acids in the SagA pre- zone of b-haemolysis surrounding colonies grown on propeptide supports the designation of SLS as a blood agar media. This phenomenon reflects complete bacteriocin-like toxin. No significant pleotrophic lysis of red blood cells produced by the potent oxygen- effects of sagA deletion were observed on M protein, stable cytolysin known as streptolysin S (SLS). SLS exists capsule or cysteine protease production. In a murine primarily in cell-bound form (Ginsburg, 1999) and is deliv- model of NF, the SLS-negative M1T1 GAS mutant was ered most effectively to target cells by direct contact with markedly diminished in its ability to produce necrotic GAS (Ofek et al., 1990). The cytolytic spectrum of SLS is skin ulcers and spread to the systemic circulation. broad including lymphocytes, neutrophils, platelets, The SLS toxin impaired phagocytic clearance and cancer cell lines and subcellular organelles (Keiser et al., promoted epithelial cell cytotoxicity, the latter pheno- 1964; Taketo and Taketo, 1966; Ginsburg, 1972; type being enhanced by the effects of M protein and Hryniewicz and Pryjma, 1977). Insertion of SLS into the streptolysin O. We conclude that all genetic compo- cell membrane results in the formation of transmembrane nents of the sag operon are required for expression pores and osmotic cell lysis, similar to that observed with of functional SLS, an important virulence factor in the complement-mediated cytotoxicity (Ginsburg, 1999; Carr pathogenesis of invasive M1T1 GAS infection. et al., 2001). The GAS chromosomal locus for SLS production was Accepted 14 January, 2005. *For correspondence. E-mail first identified by J. DeAzavedo and colleagues through [email protected]; Tel. (+1) 858 534 7408; Fax (+1) 858 534 5611. generation and analysis of SLS-deficient transposon © 2005 Blackwell Publishing Ltd 682 V. Datta et al. mutants (Borgia et al., 1997; Betschel et al., 1998). Sub- Results sequent chromosome walking studies performed by B. Requirement of individual sag locus genes in SLS Beall, and informed by the first GAS genome project production (Ferretti et al., 2001), recognized the existence of a nine- gene cluster (sagA–I for streptolysin-associated genes) in Earlier studies establishing the role of the sag locus in the region of transposon insertions. The functional bound- SLS production employed transposon mutants (Betschel aries of the sag locus were then defined by plasmid et al., 1998; Li et al., 1999) or insertional inactivation integrational mutagenesis and its organization as an mutants (Nizet et al., 2000; Biswas et al., 2001) likely to operon confirmed by RNA analysis (Nizet et al., 2000). exert polar effects on transcription of downstream genes Heterologous expression of the entire GAS sag locus in in the operon. To assess the specific requirement of indi- a non-haemolytic strain of Lactococcus lactis yielded vidual sag genes in SLS production, we combined precise robust b-haemolytic transformants, confirming that the in-frame allelic exchange mutagenesis with single-gene operon is both necessary and sufficient for SLS produc- complementation analysis. Bacterial strains used in this tion (Nizet et al., 2000). Individual gene homologies and study are listed in Table 1. GAS strain 5448 is a serotype structural features of the operon suggested that SLS is a M1T1 isolate from a patient with necrotizing fasciitis and bacteriocin-like peptide toxin, with structural gene sagA streptococcal toxic shock syndrome expressing SLS and encoding a 53-amino-acid prepropeptide precursor of the streptolysin O (SLO), cysteine protease, superantigens mature toxin (Nizet et al., 2000). This hypothesis was cor- SpeA, SpeF, SpeG and SmeZ and is genetically repre- roborated by the research group of B. Kreikemeyer (Carr sentative of the globally disseminated M1T1 clone that is et al., 2001), and later others (Dale et al., 2002), who the leading cause of invasive GAS infections (Kansal demonstrated that antibodies generated against synthetic et al., 2000). GAS strain NZ131, a serotype M49T14 skin peptides corresponding to the predicted SagA propeptide isolate from a patient with glomerulonephritis, expresses neutralized SLS activity. Highly homologous sag operons SLS and SLO, and is frequently used in genetic studies producing SLS toxins are responsible for the b-haemolytic because of its increased transformability (Simon and phenotypes of human isolates of groups C and G strep- Ferretti, 1991). Precise in-frame allelic replacement of the tococci (GCS and GGS) and the zoonotic pathogen sagA, sagB, sagC, sagD, sagE, sagF or sagG genes in Streptococcus iniae (Fuller et al., 2002; Humar et al., M49 GAS strain NZ131 produced a completely non- 2002). haemolytic phenotype (Fig. 1). Allelic replacement of Streptolysin S contributes significantly to GAS virulence sagA in the M1 GAS strain 5448 also eliminated SLS potential in animal models of infection (Betschel et al., production. Complementation experiments were per- 1998; Humar et al., 2002; Fontaine et al., 2003; Sierig formed to reintroduce the corresponding single gene to et al., 2003; Engleberg et al., 2004). Like the genetically each allelic exchange mutant. Full complementation was distinct b-haemolysin of the human pathogen group B noted for sagA, sagC and sagF, while partial complemen- Streptococcus (GBS), SLS could theoretically enhance tation was seen with sagB, sagD and sagG (Fig. 1). These GBS pathogenicity by causing direct tissue injury, promot- experiments demonstrate a unique requirement for each ing cellular invasion, impairing phagocytic clearance or of these six sag operon genes in production of functional additional yet to be defined mechanisms (Nizet, 2002). SLS toxin. We speculate that partial complementation in However, the analysis of SLS-associated virulence phe- the case of the individual genes mentioned could reflect notypes has been complicated by reports that various toxicity of overexpression (note SagB and SagD are pre- mutations in the region of the sagA gene could be dicted cytoplasmic proteins) or upsetting the stoichiome- associated with alterations in expression of other GAS try of complex assembly (SagG is predicted to participate virulence genes including M protein, cysteine protease with SagH and SagI in forming an ABC-type transporter). and streptokinase (Li et al., 1999; Biswas et al., 2001; Mangold et al., 2004). The sagE gene appears to encode an immunity function In the present study, we employ precise in-frame allelic replacement, single-gene complementation and limited Multiple initial attempts to complement the sagE allelic site-directed mutagenesis to test the specific requirement exchange mutant were unsuccessful. Because the pre- of individual GAS sag locus genes for the production of dicted gene product SagE shares homology to a bacteri- SLS. Using a precise allelic replacement DsagA mutant ocin immunity protein of Lactobacillus planterum,
Load more

Recommended publications
  • The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections
    toxins Review The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections Patience Shumba 1, Srikanth Mairpady Shambat 2 and Nikolai Siemens 1,* 1 Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, University of Greifswald, D-17489 Greifswald, Germany; [email protected] 2 Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, CH-8091 Zurich, Switzerland; [email protected] * Correspondence: [email protected]; Tel.: +49-3834-420-5711 Received: 20 May 2019; Accepted: 10 June 2019; Published: 11 June 2019 Abstract: Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies. Keywords: Streptococcus pyogenes; group A streptococcus; Staphylococcus aureus; skin infections; necrotizing soft tissue infections; pore-forming toxins; superantigens; immunomodulatory proteases; immune responses Key Contribution: Group A streptococcal and Staphylococcus aureus toxins manipulate host physiological and immunological responses to promote disease severity and progression. 1. Introduction Necrotizing soft tissue infections (NSTIs) are rare and represent a more severe rapidly progressing form of soft tissue infections that account for significant morbidity and mortality [1].
    [Show full text]
  • Biosafety Level 1 and Rdna Training
    Biosafety Level 1and rDNA Training Office of Biological Safety Biosafety Level 1 and rDNA Training • Difference between Risk Group and Biosafety Level • NIH and UC policy on recombinant DNA • Work conducted at Biosafety Level 1 • UC Code of Conduct for researchers Biosafety Level 1 and rDNA Training What is the difference between risk group and biosafety level? Risk Groups vs Biosafety Level • Risk Groups: Assigned to infectious organisms by global agencies (NIH, CDC, WHO, etc.) • In US, only assigned to human pathogens (NIH) • Biosafety Level (BSL): How the organisms are managed/contained (increasing levels of protection) Risk Groups vs Biosafety Level • RG1: Not associated with disease in healthy adults (non‐pathogenic E. coli; S. cerevisiae) • RG2: Cause diseases not usually serious and are often treatable (S. aureus; Legionella; Toxoplasma gondii) • RG3: Serious diseases that may be treatable (Y. pestis; B. anthracis; Rickettsia rickettsii; HIV) • RG4: Serious diseases with no treatment/cure (Hemorrhagic fever viruses, e.g., Ebola; no bacteria) Risk Groups vs Biosafety Level • BSL‐1: Usually corresponds to RG1 – Good microbiological technique – No additional safety equipment required for biological work (may still need chemical/radiation protection) – Ability to destroy recombinant organisms (even if they are RG1) Risk Groups vs Biosafety Level • BSL‐2: Same as BSL‐1, PLUS… – Biohazard signs – Protective clothing (lab coat, gloves, eye protection, etc.) – Biosafety cabinet (BSC) for aerosols is recommended but not always required – Negative airflow into room is recommended, but not always required Risk Groups vs Biosafety Level • BSL‐3: Same as BSL‐2, PLUS… – Specialized clothing (respiratory protection, Tyvek, etc.) – Directional air flow is required.
    [Show full text]
  • Penetration of Stratified Mucosa Cytolysins Augment Superantigen
    Cytolysins Augment Superantigen Penetration of Stratified Mucosa Amanda J. Brosnahan, Mary J. Mantz, Christopher A. Squier, Marnie L. Peterson and Patrick M. Schlievert This information is current as of September 25, 2021. J Immunol 2009; 182:2364-2373; ; doi: 10.4049/jimmunol.0803283 http://www.jimmunol.org/content/182/4/2364 Downloaded from References This article cites 76 articles, 24 of which you can access for free at: http://www.jimmunol.org/content/182/4/2364.full#ref-list-1 Why The JI? Submit online. http://www.jimmunol.org/ • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average by guest on September 25, 2021 Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2009 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Cytolysins Augment Superantigen Penetration of Stratified Mucosa1 Amanda J. Brosnahan,* Mary J. Mantz,† Christopher A. Squier,† Marnie L. Peterson,‡ and Patrick M. Schlievert2* Staphylococcus aureus and Streptococcus pyogenes colonize mucosal surfaces of the human body to cause disease. A group of virulence factors known as superantigens are produced by both of these organisms that allows them to cause serious diseases from the vaginal (staphylococci) or oral mucosa (streptococci) of the body.
    [Show full text]
  • Response of Cellular Innate Immunity to Cnidarian Pore-Forming Toxins
    Review Response of Cellular Innate Immunity to Cnidarian Pore-Forming Toxins Wei Yuen Yap 1 and Jung Shan Hwang 2,* 1 Department of Biological Sciences, School of Science and Technology, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia; [email protected] 2 Department of Medical Sciences, School of Healthcare and Medical Sciences, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia * Correspondence: [email protected]; Tel.: +603-7491-8622 (ext. 7414) Academic Editor: Jean-Marc Sabatier Received: 23 August 2018; Accepted: 28 September 2018; Published: 4 October 2018 Abstract: A group of stable, water-soluble and membrane-bound proteins constitute the pore forming toxins (PFTs) in cnidarians. They interact with membranes to physically alter the membrane structure and permeability, resulting in the formation of pores. These lesions on the plasma membrane causes an imbalance of cellular ionic gradients, resulting in swelling of the cell and eventually its rupture. Of all cnidarian PFTs, actinoporins are by far the best studied subgroup with established knowledge of their molecular structure and their mode of pore-forming action. However, the current view of necrotic action by actinoporins may not be the only mechanism that induces cell death since there is increasing evidence showing that pore-forming toxins can induce either necrosis or apoptosis in a cell-type, receptor and dose-dependent manner. In this review, we focus on the response of the cellular immune system to the cnidarian pore-forming toxins and the signaling pathways that might be involved in these cellular responses.
    [Show full text]
  • A Novel Superantigen Isolated from Pathogenic Strains of Streptococcus Pyogenes with Aminoterminal Homology to Staphylococcal Enterotoxins B and C
    A novel superantigen isolated from pathogenic strains of Streptococcus pyogenes with aminoterminal homology to staphylococcal enterotoxins B and C. J A Mollick, … , D Grossman, R R Rich J Clin Invest. 1993;92(2):710-719. https://doi.org/10.1172/JCI116641. Research Article Streptococcus pyogenes (group A Streptococcus) has re-emerged in recent years as a cause of severe human disease. Because extracellular products are involved in streptococcal pathogenesis, we explored the possibility that a disease isolate expresses an uncharacterized superantigen. We screened culture supernatants for superantigen activity with a major histocompatibility complex class II-dependent T cell proliferation assay. Initial fractionation with red dye A chromatography indicated production of a class II-dependent T cell mitogen by a toxic shock-like syndrome (TSLS) strain. The amino terminus of the purified streptococcal superantigen was more homologous to the amino termini of staphylococcal enterotoxins B, C1, and C3 (SEB, SEC1, and SEC3), than to those of pyrogenic exotoxins A, B, C or other streptococcal toxins. The molecule, designated SSA, had the same pattern of class II isotype usage as SEB in T cell proliferation assays. However, it differed in its pattern of human T cell activation, as measured by quantitative polymerase chain reaction with V beta-specific primers. SSA activated human T cells that express V beta 1, 3, 15 with a minor increase of V beta 5.2-bearing cells, whereas SEB activated V beta 3, 12, 15, and 17-bearing T cells. Immunoblot analysis of 75 disease isolates from several localities detected SSA production only in group A streptococci, and found that SSA is apparently confined to only three clonal […] Find the latest version: https://jci.me/116641/pdf A Novel Superantigen Isolated from Pathogenic Strains of Streptococcus pyogenes with Aminoterminal Homology to Staphylococcal Enterotoxins B and C Joseph A.
    [Show full text]
  • Retrograde Transport of Mutant Ricin to the Endoplasmic Reticulum with Subsequent Translocation to Cytosol (Ricin͞toxin͞translocation͞retrograde Transport͞sulfation)
    Proc. Natl. Acad. Sci. USA Vol. 94, pp. 3783–3788, April 1997 Cell Biology Retrograde transport of mutant ricin to the endoplasmic reticulum with subsequent translocation to cytosol (ricinytoxinytranslocationyretrograde transportysulfation) ANDRZEJ RAPAK,PÅL Ø. FALNES, AND SJUR OLSNES* Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway Communicated by R. John Collier, Harvard Medical School, Boston, MA, January 30, 1997 (received for review November 25, 1996) ABSTRACT Translocation of ricin A chain to the cytosol (20). Because this labeling takes place in the Golgi apparatus, only has been proposed to take place from the endoplasmic reticulum molecules that have already been transported retrograde to the (ER), but attempts to visualize ricin in this organelle have failed. Golgi complex will be labeled. Furthermore, because only the A Here we modified ricin A chain to contain a tyrosine sulfation chain carrying the sulfation site will be labeled, the B chain, which site alone or in combination with N-glycosylation sites. When migrates at almost the same rate as the modified A chain, will not reconstituted with ricin B chain and incubated with cells in the complicate the interpretation of the data. We here present 35 presence of Na2 SO4, the modified A chains were labeled. The evidence that sulfated ricin A chain is transported retrograde to labeling was prevented by brefeldin A and ilimaquinone, and it the ER and then translocated to the cytosol. appears to take place in the Golgi apparatus. This method allows selective labeling of ricin molecules that have already been MATERIALS AND METHODS 35 transported retrograde to this organelle.
    [Show full text]
  • Functional Classification of Protein Toxins As a Basis for Bioinformatic
    www.nature.com/scientificreports OPEN Functional classifcation of protein toxins as a basis for bioinformatic screening Received: 27 July 2017 Surendra S. Negi1, Catherine H. Schein1,2, Gregory S. Ladics3, Henry Mirsky4, Peter Chang4, Accepted: 2 October 2017 Jean-Baptiste Rascle5, John Kough6, Lieven Sterck 7, Sabitha Papineni8, Joseph M. Jez9, Published: xx xx xxxx Lucilia Pereira Mouriès10 & Werner Braun1 Proteins are fundamental to life and exhibit a wide diversity of activities, some of which are toxic. Therefore, assessing whether a specifc protein is safe for consumption in foods and feeds is critical. Simple BLAST searches may reveal homology to a known toxin, when in fact the protein may pose no real danger. Another challenge to answer this question is the lack of curated databases with a representative set of experimentally validated toxins. Here we have systematically analyzed over 10,000 manually curated toxin sequences using sequence clustering, network analysis, and protein domain classifcation. We also developed a functional sequence signature method to distinguish toxic from non-toxic proteins. The current database, combined with motif analysis, can be used by researchers and regulators in a hazard screening capacity to assess the potential of a protein to be toxic at early stages of development. Identifying key signatures of toxicity can also aid in redesigning proteins, so as to maintain their desirable functions while reducing the risk of potential health hazards. Most genetically engineered (GE) food crops involve expressing an introduced protein, thus assessing the safety of the protein is required before commercialization1–4. GE crops are created by introducing gene(s) from one species into a crop plant species to improve the nutritional value, yield, drought resistance, herbicide tolerance or pest resistance.
    [Show full text]
  • Effect of Streptolysin O on Erythrocyte Membranes, Liposomes, and Lipid Dispersions
    EFFECT OF STREPTOLYSIN O ON ERYTHROCYTE MEMBRANES, LIPOSOMES, AND LIPID DISPERSIONS A Protein-Cholesterol Interaction JAMES L. DUNCAN and RICHARD SCHLEGEL From the Departments of Microbiology and Pathology, Northwestern University Medical and Dental Schools, Chicago, Illinois 60611. Dr. Schlegel's present address is the Department of Pathology, Peter Bent Brigham Hospital, Harvard University Medical School, Boston, Massachusetts 02115. Downloaded from http://rupress.org/jcb/article-pdf/67/1/160/1266643/160.pdf by guest on 01 October 2021 ABSTRACT The effect of the bacterial cytolytic toxin, streptolysin O (SLO), on rabbit erythrocyte membranes, liposomes, and lipid dispersions was examined. SLO produced no gross alterations in the major erythrocyte membrane proteins or lipids. However, when erythrocytes were treated with SLO and examined by electron microscopy, rings and "C"-shaped structures were observed in the cell membrane. The rings had an electron-dense center, 24 nm in diameter, and the overall diameter of the structure was 38 nm. Ring formation also occurred when erythrocyte membranes were fixed with glutaraldehyde and OsO4 before the addition of toxin. In contrast, rings were not seen when erythrocytes were treated with toxin at 0~ indicating that adsorption of SLO to the membrane is not sufficient for ring formation since toxin is known to bind to erythrocytes at that temperature. The ring structures were present on lecithin-cholesterol-dicetylphos- phate liposomes after SLO treatment, but there was no release of the trapped, internal markers, K2CrO4 or glucose. The crucial role of cholesterol in the formation of rings and C's was demonstrated by the fact that these structures were present in toxin-treated cholesterol dispersions, but not in lecithin-dicetylphosphate dispersions nor in the SLO preparations alone.
    [Show full text]
  • From the Alfred I. Du Pont Institute, Wilmington, Deleware) Pr~S 33 ~O 41 (Received for Publication, January 7, 1957)
    THE LEUKOTOXIC ACTION OF STREPTOCOCCI* Bx ARMINE T. WILSON, M.D. (From the Alfred I. du Pont Institute, Wilmington, Deleware) Pr~s 33 ~o 41 (Received for publication, January 7, 1957) This is the third study in a series on the interactions between streptococci and host cells. Previous reports have concerned the egestion of streptococci by phagocytic cells (1), and the failure of streptococci to lose their capacity of resisting phagocytosis after being killed with gentle heat or ultraviolet radiation (2). The present work is concerned with one type of outcome fol- lowing phagocytosis; namely, the destruction of the phagocytizing leuko- cytes which occurs when certain strains of streptococci are ingested. This injury will be called here "leukotoxic action," and the pertinent attribute of injurious streptococci will be called "leukotoxicity." It was described by Levaditi in 1918 (3), but has received no attention since that time as far as we have been able to discover. The leukotoxic effect is seen only after intact cocci have been phagocytized. It must not be confused with the action of streptococcal leukocidin, a soluble substance elaborated into the medium by growing cocci, which destroys leuko- cytes even when all coccal cells have been removed by filtration. Todd has presented impressive evidence indicating that leukocidin and streptolysin O are identical (4). In the present report consideration will be given to the biological charac- teristics of leukotoxicity, to its distribution among streptococci, its relation to other known streptococcal products, its relationship to virulence and its possible significance in streptococcal disease. Materials and Methods Strains.--Streptococei of the several serological groups and of types within group A have been accumulated from numerous sources, chiefly from Dr.
    [Show full text]
  • Functional Consequences of Calcium Influx Promoted by Bacterial Pore
    toxins Review Functional Consequences of Calcium Influx Promoted by Bacterial Pore-Forming Toxins Stéphanie Bouillot, Emeline Reboud and Philippe Huber * Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France; [email protected] (S.B.); [email protected] (E.R.) * Correspondence: [email protected] Received: 3 September 2018; Accepted: 20 September 2018; Published: 25 September 2018 Abstract: Bacterial pore-forming toxins induce a rapid and massive increase in cytosolic Ca2+ concentration due to the formation of pores in the plasma membrane and/or activation of Ca2+-channels. As Ca2+ is an essential messenger in cellular signaling, a sustained increase in Ca2+ concentration has dramatic consequences on cellular behavior, eventually leading to cell death. However, host cells have adapted mechanisms to protect against Ca2+ intoxication, such as Ca2+ efflux and membrane repair. The final outcome depends upon the nature and concentration of the toxin and on the cell type. This review highlights the repercussions of Ca2+ overload on the induction of cell death, repair mechanisms, cellular adhesive properties, and the inflammatory response. Keywords: host–pathogen interaction; bacterial virulence factor; cell death; signal transduction; ion flux Key Contribution: This review summarizes the numerous host cell alterations induced by Ca2+ overload triggered by bacterial pore-forming toxins, as well as the defense mechanisms implemented by the host to limit Ca2+ intoxication and plasma membrane perforation. 1. Introduction Bacterial pore-forming toxins (PFTs) are the most frequently encountered virulence factors among bacterial pathogens [1–4]. They are secreted in the extracellular milieu from Gram-negative and Gram-positive bacteria by various bacterial secretion systems.
    [Show full text]
  • Functional Effects of Anti-Neuronal Antibodies in Patients with Encephalitis Lethargica and Related Disorders Associated with Streptococcal Infection
    Functional effects of anti-neuronal antibodies in patients with encephalitis lethargica and related disorders associated with streptococcal infection PRIYAMVADA DUA Queen Mary University of London Submitted for the Degree of Doctor of Philosophy (PhD) 1 DEDICATION I would like to dedicate this thesis to my MOTHER 2 ACKNOWLEDGEMENTS It would not have been possible to write this doctoral thesis without the help and support of people around me, to only some of whom it is possible to give particular mention here. This thesis would not have been possible without the advice, support and clinical knowledge of my principal supervisor and mentor, Prof. Gavin Giovannoni. The help, support and research expertise of my second supervisor, Prof. David Baker. I would especially like to thank Dr. Ute Meier for her trust, constant encouragement and both professional and personal advice at all times. Their input has been invaluable and instrumental on both an academic and a personal level, for which I am extremely grateful. I would like to thanks members of the Blizard Institute for the use of their facilities, equipment and the warm welcome, especially Dr. Gary Warnes for his help with Flow Cytometry and Dr. Ann Wheeler for her help with Microscopy. Special mention goes to Dr. Veronika Souslova whose expertise in molecular biology made a large part of this project possible. Additionally I would like to acknowledge: Dr. Kathryn Harris (Great Ormond Street Hospital, London) for her guidance, help and use of facilities for all the streptococcal work and Prof. Angela Vincent and her team (WIMM, University of Oxford) for providing the facilities to carry out the NMDAR and VGKC assays.
    [Show full text]
  • Streptolysin O (S5265 and S0149)
    Streptolysin O from Streptococcus pyogenes Catalog Numbers S5265 and S0149 Storage Temperature 2–8 °C CAS RN 98072-47-0 Precautions and Disclaimer Synonym: SLO This product is for R&D use only, not for drug, household, or other uses. Please consult the Material Product Description Safety Data Sheet for information regarding hazards Streptolysin O (SLO) is a single polypeptide chain that and safe handling practices. is not glycosylated. It has a molecular mass of ~69 kDa1,2 and an isoelectric point (pI) of 6.0-6.4.1 Preparation Instructions SLO is soluble in cold water (1 mg/ml). Reconstitute by Streptolysin O is an immunogenic, oxygen-labile toxin, adding water into the vial and gently rotating. which is reversibly activated by dithiothreitol.2 It is released into the extracellular medium along with other After reconstitution, the solution should be stored at toxins, including streptolysin S, during the growth of -20 °C in aliquots and any unused portions should be most strains of group A and many strains of groups C discarded. SLO is readily oxidized in solution. The and G Streptococci.2,3 Streptolysin S differs from SLO in activity is significantly increased in the presence of that it is oxygen-stable, nonimmunogenic and only reducing agents, 20 mM cysteine3 or 10 mM 4 1 active when associated with a carrier protein. SLO dithiothreitol. A SLO solution will lose ~50% activity may be used for cell permeabilization or hemolysis. within 10 days when stored at 2-8 °C. It is Erythrocytes from different animal species have recommended to freeze solutions at a minimal significantly different susceptibility to hemolysis by concentration of 0.2 mg/ml.
    [Show full text]