scholarly journals Analysis of two-component sensor proteins involved in the response to acid stimuli in Streptococcus pyogenes

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3187-3194 ◽  
Author(s):  
Mariko Ichikawa ◽  
Masaaki Minami ◽  
Masanori Isaka ◽  
Ichiro Tatsuno ◽  
Tadao Hasegawa
Keyword(s):  
Environmental Factors ◽  
Streptococcus Pyogenes ◽  
Parental Strain ◽  
Clinical Strain ◽  
Infection Model ◽  
Knockout Strain ◽  
Mouse Infection Model ◽  
Two Component ◽  
Sensor Protein ◽  
Sensor Proteins

The virulence of Streptococcus pyogenes depends on proteins that are produced by this bacterium. The production of virulence proteins depends on environmental factors, and two-component regulatory systems are considered to be involved in sensing these factors. One of the environmental factors is acid stimuli. We established knockout strains in all speculated two-component regulatory sensor proteins of the M1 clinical strain of S. pyogenes and examined their relevance to acid stimuli. The parental strain and its derived knockout strains were cultured in a medium adjusted to pH 7.6 or 6.0, and their growth in broth was compared. The spy1622 sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1622 two-component sensor protein is involved in sensing acid stimuli. To further examine the role of the Spy1622 two-component sensor protein in virulence, blood bactericidal assays and mouse infection model experiments were performed. We found that the spy1622 knockout strain was less virulent than the parental strain, which suggests that the Spy1622 two-component sensor protein could play an important role in virulence.

Deciphering the interactions of Streptococcus pyogenes and the complement system using a novel mouse infection model

Immunobiology ◽  
2012 ◽  
Vol 217 (11) ◽  
pp. 1163
Author(s):  
David Ermert ◽  
Jutamas Shaughnessy ◽  
Inga-Maria Frick ◽  
Johan Malmström ◽  
Lars Björck ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Complement System ◽  
Infection Model ◽  
Mouse Infection Model ◽  
Mouse Infection ◽  
The Complement System

Characterization of a virulence-associated and cell-wall-located DNase of Streptococcus pyogenes

Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 184-190 ◽  
Author(s):  
Tadao Hasegawa ◽  
Masaaki Minami ◽  
Akira Okamoto ◽  
Ichiro Tatsuno ◽  
Masanori Isaka ◽  
...  
Keyword(s):  
Cell Wall ◽  
Streptococcus Pyogenes ◽  
Protein A ◽  
Insoluble Fraction ◽  
Infection Model ◽  
Two Dimensional Gel Electrophoresis ◽  
Mouse Infection Model ◽  
Peptide Mass ◽  
A Cell

We investigated culture supernatant proteins from the M1 serotype of Streptococcus pyogenes by two-dimensional gel electrophoresis and peptide mass mapping analysis, and characterized the single protein spots. Among them, we analysed the Spy0747 protein. This protein is homologous to the SsnA protein, a cell-wall-located DNase expressed in Streptococcus suis serotype 2. We designated the Spy0747 protein as SpnA. SpnA protein was also detected in the insoluble fraction of whole-cell lysates using shotgun proteomic analysis, suggesting that SpnA is also located in the cell wall. SpnA was expressed as a glutathione S-transferase-fusion protein in Escherichia coli. We confirmed that the recombinant protein had DNase activity that was dependent on Ca2+ and Mg2+, like SsnA. Blood bactericidal assays and mouse infection model experiments showed that the spnA knockout strain was less virulent than the parental strain, thus suggesting that SpnA could play an important role in virulence. Using PCR, we found that the spnA gene was present in all clinical S. pyogenes strains we examined. Our results, together with a previous report identifying Spy0747 as a surface-associated protein, suggest that SpnA is an important cell-wall-located DNase that is generally produced in S. pyogenes and is involved in virulence.

scholarly journals SpyA, a C3-Like ADP-Ribosyltransferase, Contributes to Virulence in a Mouse Subcutaneous Model of Streptococcus pyogenes Infection

2011 ◽  
Vol 79 (6) ◽  
pp. 2404-2411 ◽  
Author(s):  
Jessica S. Hoff ◽  
Mark DeWald ◽  
Steve L. Moseley ◽  
Carleen M. Collins ◽  
Jovanka M. Voyich
Keyword(s):  
Streptococcus Pyogenes ◽  
Lesion Size ◽  
Infected Tissue ◽  
Infection Model ◽  
Mrna Levels ◽  
Wild Type ◽  
Gene Encoding ◽  
Content Type ◽  
Mouse Infection Model ◽  
Adp Ribosyltransferase

ABSTRACTStreptococcus pyogenesis an important human pathogen with an expansive repertoire of verified and putative virulence factors. Here we demonstrate that a mutant deficient in the production of the streptococcal ADP-ribosyltransferase SpyA generates lesions of reduced size in a subcutaneous mouse infection model. At early stages of infection, when the difference in lesion size is first established, inflamed tissue isolated from lesions of mice infected withspyAmutant bacteria has higher levels of mRNA encoding the chemokines CXCL1 and CCL2 than does tissue isolated from mice infected with wild-type bacteria. In addition, at these early times, the mRNA levels for the gene encoding the intermediate filament vimentin are higher in the mutant-infected tissue. As wound resolution progresses, mRNA levels of the gene encoding matrix metallopeptidase 2 are lower in mutant-infected tissue. Furthermore, we demonstrate that thespyAmutant is internalized more efficiently than wild-type bacteria by HeLa cells. We conclude that SpyA contributes to streptococcal pathogenesis in the mouse subcutaneous infection model. Our observations suggest that the presence of SpyA delays wound healing in this model.

scholarly journals Silencing and Reactivation of Urease inYersinia pestis Is Determined by One G Residue at a Specific Position in the ureD Gene

2001 ◽  
Vol 69 (1) ◽  
pp. 170-176 ◽  
Author(s):  
Florent Sebbane ◽  
Annie Devalckenaere ◽  
Jeannine Foulon ◽  
Elisabeth Carniel ◽  
Michel Simonet
Keyword(s):  
Parental Strain ◽  
Urease Activity ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Infection Model ◽  
Mouse Infection Model ◽  
Lethal Infection ◽  
Specific Position ◽  
Species Specific

ABSTRACT Yersinia pestis, the plague agent, is a naturally nonureolytic microorganism, while all other Yersiniaspecies display a potent urease activity. In this report we demonstrate that Y. pestis harbors a complete urease locus composed of three structural (ureABC) and four accessory (ureEFGD) genes. Absence of ureolytic activity is due to the presence of one additional G residue in a poly(G) stretch, which introduces a premature stop codon in ureD. The presence of the same additional G in eight other Y. pestis isolates indicates that this mutation is species specific. Spontaneous excision of the extra G occurs at a frequency of 10−4 to 10−5 and restores a ureolytic phenotype to Y. pestis. The virulence of two independent ureolytic clones ofY. pestis injected either intravenously, subcutaneously, or intragastrically did not differ from that of the parental strain in the mouse infection model. Coinfection experiments with an equal number of ureolytic and nonureolytic bacteria did not evidence any difference in the ability of the two variants to multiply in vivo and to cause a lethal infection. Altogether our results demonstrate that variation of one extra G residue in ureD determines the ureolytic activity of Y. pestis but does not affect its virulence for mice or its ability to multiply and disseminate.

scholarly journals Two-Component Systems of Helicobacter pylori Contribute to Virulence in a Mouse Infection Model

2003 ◽  
Vol 71 (9) ◽  
pp. 5381-5385 ◽  
Author(s):  
Klaus Panthel ◽  
Patricia Dietz ◽  
Rainer Haas ◽  
Dagmar Beier
Keyword(s):  
Helicobacter Pylori ◽  
Transcriptional Control ◽  
Response Regulator ◽  
Infection Model ◽  
Histidine Kinases ◽  
Reading Frame ◽  
Mouse Infection Model ◽  
Regulatory Systems ◽  
Two Component ◽  
H Pylori

ABSTRACT Helicobacter pylori encodes three histidine kinases and five response regulators belonging to the family of two-component regulatory systems which are involved in transcriptional control. Here we demonstrate that isogenic mutants of H. pylori P76 with deletions of the response regulator open reading frame (ORF) HP1365 and ORFs HP244, HP165, and HP1364 encoding histidine kinases are unable to colonize the stomachs of BALB/c mice, suggesting an essential role of these systems in the regulation of important virulence properties of H. pylori. Furthermore, we demonstrate that the genes under the control of the PHP1408 and PHP119 promoters which are regulated by the two-component system HP166-HP165 are not essential for single mutant colonization of mice but are required under competitive colonization conditions.

scholarly journals Generation and Characterization of a Defined Mutant of Streptococcus suis Lacking Suilysin

2001 ◽  
Vol 69 (4) ◽  
pp. 2732-2735 ◽  
Author(s):  
Andrew G. Allen ◽  
Steven Bolitho ◽  
Heather Lindsay ◽  
Shahid Khan ◽  
Clare Bryant ◽  
...  
Keyword(s):  
Parental Strain ◽  
Porcine Model ◽  
Systemic Infection ◽  
Streptococcus Suis ◽  
Infection Model ◽  
Gene Encoding ◽  
European Isolate ◽  
Mouse Infection Model ◽  
Allelic Replacement

ABSTRACT A defined allelic-replacement mutant of the sly gene, encoding a thiol-activated cytolysin, from a European isolate ofStreptococcus suis serotype 2 was generated and characterized. Unlike the parental strain, it is nonhemolytic, noncytotoxic for cultured macrophage-like cells, avirulent in a mouse infection model, yet only slightly attenuated in a porcine model of systemic infection.

scholarly journals An epitope-based malaria vaccine targeting the junctional region of circumsporozoite protein

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Lucie Jelínková ◽  
Hugo Jhun ◽  
Allison Eaton ◽  
Nikolai Petrovsky ◽  
Fidel Zavala ◽  
...  
Keyword(s):  
Mouse Model ◽  
Malaria Vaccine ◽  
High Titer ◽  
Circumsporozoite Protein ◽  
Infection Model ◽  
Vaccine Platform ◽  
Junctional Region ◽  
Mouse Infection Model ◽  
Virus Like Particle ◽  
Major Surface

AbstractA malaria vaccine that elicits long-lasting protection and is suitable for use in endemic areas remains urgently needed. Here, we assessed the immunogenicity and prophylactic efficacy of a vaccine targeting a recently described epitope on the major surface antigen on Plasmodium falciparum sporozoites, circumsporozoite protein (CSP). Using a virus-like particle (VLP)-based vaccine platform technology, we developed a vaccine that targets the junctional region between the N-terminal and central repeat regions of CSP. This region is recognized by monoclonal antibodies, including mAb CIS43, that have been shown to potently prevent liver invasion in animal models. We show that CIS43 VLPs elicit high-titer and long-lived anti-CSP antibody responses in mice and is immunogenic in non-human primates. In mice, vaccine immunogenicity was enhanced by using mixed adjuvant formulations. Immunization with CIS43 VLPs conferred partial protection from malaria infection in a mouse model, and passive transfer of serum from immunized macaques also inhibited parasite liver invasion in the mouse infection model. Our findings demonstrate that a Qβ VLP-based vaccine targeting the CIS43 epitope combined with various adjuvants is highly immunogenic in mice and macaques, elicits long-lasting anti-CSP antibodies, and inhibits parasite infection in a mouse model. Thus, the CIS43 VLP vaccine is a promising pre-erythrocytic malaria vaccine candidate.

scholarly journals Phage Resistance Is Associated with Decreased Virulence in KPC-Producing Klebsiella pneumoniae of the Clonal Group 258 Clade II Lineage

2021 ◽  
Vol 9 (4) ◽  
pp. 762
Author(s):  
Lucia Henrici De Angelis ◽  
Noemi Poerio ◽  
Vincenzo Di Pilato ◽  
Federica De Santis ◽  
Alberto Antonelli ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Parental Strain ◽  
Bacterial Infections ◽  
Capsular Polysaccharide ◽  
Galleria Mellonella ◽  
Bacterial Pathogen ◽  
Phage Resistance ◽  
Infection Model ◽  
Lytic Phage ◽  
Susceptible Host

Phage therapy is now reconsidered with interest in the treatment of bacterial infections. A major piece of information for this application is the definition of the molecular targets exploited by phages to infect bacteria. Here, the genetic basis of resistance to the lytic phage φBO1E by its susceptible host Klebsiella pneumoniae KKBO-1 has been investigated. KKBO-1 phage-resistant mutants were obtained by infection at high multiplicity. One mutant, designated BO-FR-1, was selected for subsequent experiments, including virulence assessment in a Galleria mellonella infection model and characterization by whole-genome sequencing. Infection with BO-FR-1 was associated with a significantly lower mortality when compared to that of the parental strain. The BO-FR-1 genome differed from KKBO-1 by a single nonsense mutation into the wbaP gene, which encodes a glycosyltransferase involved in the first step of the biosynthesis of the capsular polysaccharide (CPS). Phage susceptibility was restored when BO-FR-1 was complemented with the constitutive wbaP gene. Our results demonstrated that φBO1E infects KKBO-1 targeting the bacterial CPS. Interestingly, BO-FR-1 was less virulent than the parental strain, suggesting that in the context of the interplay among phage, bacterial pathogen and host, the emergence of phage resistance may be beneficial for the host.

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