scholarly journals Flagellin genes of Yersinia enterocolitica biotype 1A: playground of evolution towards novel flagellin functions

2010 ◽  
Vol 1 (1) ◽  
pp. 7 ◽  
Author(s):  
Daniela Lepka ◽  
Gottfried Wilharm
Keyword(s):  
Yersinia Enterocolitica ◽  
Sigma Factor ◽  
Selection Pressure ◽  
Sequence Data ◽  
Sequence Polymorphism ◽  
Infection Model ◽  
Flagellin Gene ◽  
Enterocolitica Strain ◽  
Mouse Infection Model ◽  
High Pathogenic

Yersinia enterocolitica strain 8081, representing the high-pathogenic biotype 1B, harbours three flagellin genes arranged in tandem in the order fliC3, fliC, fliC2. The genes are organized monocistronic but coordinately expressed under the control of the flagellar sigma factor. No sequence data is available on flagellins of low-pathogenic Y. enterocolitica biotypes 2-5 and of biotype 1A strains, appearing non-pathogenic in the mouse infection model. We sequenced the flagellin genes of ten biotype 1A and biotype 4 isolates, respectively. While we could not identify any sequence polymorphism among flagellin genes of biotype 4 isolates, we found that biotype 1A strains harbour three variable flagellin genes. Moreover, three biotype 1A isolates exhibited a rearranged flagellin gene order and at least one rearranged flagellin gene was apparently acquired by horizontal gene transfer. The variability of flagellin genes seems to mirror evolution towards novel flagellin functions. By contrast, strictly conserved flagellins of biotype 4 isolates point at a strong selection pressure such as expected to be imposed by an important function in the context of infection.

Contribution of Toll-like receptors 2 and 4 in an oral Yersinia enterocolitica mouse infection model

2003 ◽  
Vol 293 (5) ◽  
pp. 341-348 ◽  
Author(s):  
Andreas Sing ◽  
Natalia Tvardovskaia ◽  
Dagmar Rost ◽  
Carsten J. Kirschning ◽  
Hermann Wagner ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
Infection Model ◽  
Toll Like Receptors ◽  
Mouse Infection Model ◽  
Mouse Infection

scholarly journals Yersinia enterocolitica Targets Cells of the Innate and Adaptive Immune System by Injection of Yops in a Mouse Infection Model

2009 ◽  
Vol 5 (8) ◽  
pp. e1000551 ◽  
Author(s):  
Martin Köberle ◽  
Annegret Klein-Günther ◽  
Monika Schütz ◽  
Michaela Fritz ◽  
Susanne Berchtold ◽  
...  
Keyword(s):  
Immune System ◽  
Yersinia Enterocolitica ◽  
Adaptive Immune System ◽  
Infection Model ◽  
Adaptive Immune ◽  
Mouse Infection Model ◽  
Mouse Infection

scholarly journals Detection of N-(3-Oxohexanoyl)-l-Homoserine Lactone in Mice Infected with Yersinia enterocolitica Serotype O8

2003 ◽  
Vol 71 (11) ◽  
pp. 6624-6626 ◽  
Author(s):  
Christoph A. Jacobi ◽  
Alexandra Bach ◽  
Leo Eberl ◽  
Anette Steidle ◽  
Jürgen Heesemann
Keyword(s):  
Yersinia Enterocolitica ◽  
Culture Supernatant ◽  
Homoserine Lactone ◽  
Mouse Tissue ◽  
Infection Model ◽  
Signal Molecules ◽  
Mouse Infection Model ◽  
Layer Chromatography

ABSTRACT Yersinia enterocolitica synthesizes N-acyl-l-homoserine lactone (AHL) signal molecules via the LuxR-LuxI homologues YenR-YenI. In this study we checked two prototypes of mouse-virulent Y. enterocolitica serotype O8 strains WA-314 and 8081 for AHL production in vitro and in vivo (mouse infection model). We used thin-layer chromatography in combination with the Escherichia coli AHL biosensor to identify the AHL species produced. We detected only OHHL [N-(3-oxohexanoyl)-l-homoserine lactone] and not HHL (N-hexanoyl-l-homoserine lactone) produced by Y. enterocolitica O8 in culture supernatant or infected mouse tissue. This is the first report demonstrating AHL production by yersiniae during infection.

Characterization of monoclonal antibodies to Yersinia enterocolitica iron-regulated proteins

1995 ◽  
Vol 41 (7) ◽  
pp. 562-571 ◽  
Author(s):  
Cora Kooi ◽  
Pamela A. Sokol
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Yersinia Enterocolitica ◽  
Iron Acquisition ◽  
Proteinase K ◽  
Infection Model ◽  
Mouse Infection Model ◽  
Molecular Masses ◽  
Proteinase K Treatment

Yersinia enterocolitica 1165 (0:8) expressed several iron-regulated proteins with molecular masses of 240, 194, 80, 79, 70, and 67 kDa. These proteins were not detected in cells grown in iron-rich conditions. Cell surface iodination indicated that the 240- and 190-kDa proteins (HMWPs) were not surface exposed, whereas the 67- and 70-kDa proteins appeared to be exposed to the cell surface. Incubation with iron protected the 67- and 70-kDa proteins from proteinase K treatment, suggesting that they may be involved in iron acquisition. Monoclonal antibodies (MAbs) were produced against the HMWPs and the 67-kDa iron-regulated protein. MAbs to the HMWPs not only recognized the 240- and 194-kDa proteins but also reacted with the 67- and 70-kDa iron-regulated proteins. Similarly, MAbs to the 67-kDa protein reacted with the 67- and 70-kDa proteins and the HMWPs, suggesting that these iron-regulated proteins are related immunologically. In addition, the MAbs recognized the 67- and 70-kDa proteins and HMWPs from other Y. enterocolitica serotypes, suggesting that the antigenic sites recognized on these iron-regulated proteins are conserved. The MAbs examined did not inhibit iron binding or iron uptake and did not provide protection against a Y. enterocolitica 1165 (0:8) infection in a systemic mouse infection model. Although these MAbs were not protective in this model, these iron-regulated proteins may play a role in iron acquisition and virulence, but the MAbs examined are probably not directed against epitopes involved in iron acquisition or virulence.Key words: Yersinia enterocolitica, monoclonal antibodies, iron-regulated proteins.

scholarly journals Analysis of Yersinia enterocolitica invasin expression in vitro and in vivo using a novel luxCDABE reporter system

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2734-2745 ◽  
Author(s):  
Janja Trček ◽  
Thilo M. Fuchs ◽  
Konrad Trülzsch
Keyword(s):  
Yersinia Enterocolitica ◽  
Binding Capacity ◽  
Growth Conditions ◽  
Infection Model ◽  
Reporter System ◽  
Background Strain ◽  
Serotype O ◽  
Mouse Infection Model

A novel luxCDABE plasmid for the analysis of promoter elements by site-specific integration into the genome of Yersinia enterocolitica was constructed. The versatility of this reporter system was demonstrated by comparing the activity of the inv promoter in the Y. enterocolitica high-pathogenic serotype O : 8 (strain WA-314) with that of the low pathogenic serotype O : 9 (strain Y127). The luciferase activity of a transcriptional fusion between the inv promoter of serotype O : 8 and luxCDABE was about fourfold lower than the activity of the respective O : 9 promoter. This correlated with lower invasin production by Y. enterocolitica serotype O : 8 compared with serotypes O : 9, O : 3 and O : 5,27. However, Y. enterocolitica of serotype O : 8 revealed higher invasiveness than serotype O : 9. When both invasins were expressed in trans at similar levels in the Y. enterocolitica O : 8 Δinv background strain, cell invasion assays showed a slightly higher invasiveness of the strain producing Inv(O : 8) than the strain producing Inv(O : 9). We provide experimental evidence that this might be due to a higher binding capacity of Inv(O : 8) for cells expressing β1 integrins compared with Inv(O:9). The Y. enterocolitica O : 8 strain harbouring the P inv (O : 8) : : luxCDABE fusion was then successfully used to follow inv expression in a mouse infection model. These experiments showed for the first time that the inv promoter is active in infected living mice, especially in Peyer's patches of the ileum, the caecal lymph follicle, and the lymph nodes, liver and spleen. The production of invasin in the spleen was demonstrated by Western blot analysis. In conclusion, the presented reporter system enables stable genomic integration of the luxCDABE operon into the chromosome of Yersinia, facilitates in vitro quantification of promoter activities under different bacterial growth conditions, and enables detection of promoter activities in a mouse model.

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.

Emergence of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae in vivo

2019 ◽  
Vol 74 (11) ◽  
pp. 3211-3216 ◽  
Author(s):  
Stephan Göttig ◽  
Denia Frank ◽  
Eleonora Mungo ◽  
Anika Nolte ◽  
Michael Hogardt ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Selection Pressure ◽  
Galleria Mellonella ◽  
Phenotypic Characterization ◽  
Infection Model ◽  
Development Of Resistance ◽  
Time Kill

Abstract Objectives The β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is active against KPC-producing Enterobacterales. Herein, we present molecular and phenotypic characterization of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae that emerged in vivo and in vitro. Methods Sequence analysis of blaKPC-3 was performed from clinical and in vitro-generated ceftazidime/avibactam-resistant K. pneumoniae isolates. Time–kill kinetics and the Galleria mellonella infection model were applied to evaluate the activity of ceftazidime/avibactam and imipenem alone and in combination. Results The ceftazidime/avibactam-resistant clinical K. pneumoniae isolate revealed the amino acid change D179Y in KPC-3. Sixteen novel mutational changes in KPC-3 among in vitro-selected ceftazidime/avibactam-resistant isolates were described. Time–kill kinetics showed the emergence of a resistant subpopulation under selection pressure with either imipenem or ceftazidime/avibactam. However, combined selection pressure with imipenem plus ceftazidime/avibactam prevented the development of resistance and resulted in bactericidal activity. Concordantly, the G. mellonella infection model revealed that monotherapy with ceftazidime/avibactam is prone to select for resistance in vivo and that combination therapy with imipenem results in significantly better survival. Conclusions Ceftazidime/avibactam is a valuable antibiotic against MDR and carbapenem-resistant Enterobacterales. Based on time–kill kinetics as well as an in vivo infection model we postulate a combination therapy of ceftazidime/avibactam and imipenem as a strategy to prevent the development of ceftazidime/avibactam resistance in KPC-producing Enterobacterales in vivo.

scholarly journals The zinc transporter ZnuABC is critical for the virulence of Chromobacterium violaceum and contributes to diverse zinc-dependent physiological processes

2021 ◽  
Author(s):  
Renato E. R. S. Santos ◽  
Waldir P. da Silva Júnior ◽  
Simone A. Harrison ◽  
Eric P Skaar ◽  
Walter J. Chazin ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Zinc Uptake ◽  
Chromobacterium Violaceum ◽  
Host Protein ◽  
Infection Model ◽  
Uptake System ◽  
Environmental Bacterium ◽  
Mouse Infection Model ◽  
Synthetic Metal

Chromobacterium violaceum is a ubiquitous environmental bacterium that causes sporadic life-threatening infections in humans. How C. violaceum acquires zinc to colonize environmental and host niches is unknown. In this work, we demonstrated that C. violaceum employs the zinc uptake system ZnuABC to overcome zinc limitation in the host, ensuring the zinc supply for several physiological demands. Our data indicated that the C. violaceum ZnuABC transporter is encoded in a zur-CV_RS15045-CV_RS15040-znuCBA operon. This operon was repressed by the zinc uptake regulator Zur and derepressed in the presence of the host protein calprotectin (CP) and the synthetic metal chelator EDTA. A ΔznuCBA mutant strain showed impaired growth under these zinc-chelated conditions. Moreover, the deletion of znuCBA provoked a reduction in violacein production, swimming motility, biofilm formation, and bacterial competition. Remarkably, the ΔznuCBA mutant strain was highly attenuated for virulence in an in vivo mouse infection model and showed a low capacity to colonize the liver, grow in the presence of CP, and resist neutrophil killing. Overall, our findings demonstrate that ZnuABC is essential for C. violaceum virulence, contributing to subvert the zinc-based host nutritional immunity.

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