subject:(T6SS)

University of Victoria

1. Robb, Craig. Structural biology of the type six secretion system.

Degree: Department of Biochemistry and Microbiology, 2015, University of Victoria

► The bacterial type six secretion system (T6SS) is an injectisome responsible for the translocation of effector molecules directly into host cells or competing bacteria. The… (more)

▼ The bacterial type six secretion system (T6SS) is an injectisome responsible for the translocation of effector molecules directly into host cells or competing bacteria. The system is widely distributed among proteobacteria and is found in both clinically relevant strains as well as environmental stains and represents an important system for the study of both microbial ecology and virulence. The apparatus itself is believed to have arisen from a combination of genes from bacteria and bacteriophage due to seqeuence and structural identity between T6SS components and structural bacteriophage proteins. The current model of the T6SS apparatus consists essentially of an inverted phage body that is attached to the donor cell membrane complex. The phage-like structure can contract and force a sharp needle point complex along with effector proteins into the target cell. The phage derived components have received a considerable amount of attention and the mode of assembly is relatively well understood. However, little detailed information on the assembly and function of the membrane embedded complex is available. The first major goal of this thesis was to structurally characterize the proteins of the membrane embedded complex of the type six secretion system. The structures of IglE and TssL from Francisella sp. were solved and represent a platform for further characterization of the T6SS assembly and function. The periplasmic domain of a TssL homologue from P. aeruginosa was also solved and this structure represents a subset of evolved TssL proteins that bind peptidoglycan through an unknown mechanism. Biochemical and structural analysis probed this system but came short of a definitive model for peptidoglycan binding. However, the data collected from this study will further the field of peptidoglycan binding modules and help to characterise differences among T6SSs. The translocated proteins of the T6SS are often bactericidal and attack the peptidoglycan, lipid bilayer or DNA of the target cell. However, one secreted substrate, Tse2 from Pseudomonas aeruginosa is targeted to other neighbouring cells of the same species. This toxin shares no sequence identity with any known protein but has been shown to be toxic to not only bacteria but also yeast and mammalian cells. The structure of the complex between Tse2 and its immunity protein was solved and led to two interrelated discoveries. The first was that the molecular details behind the immunity protein inhibiting Tse2 where it binds directly to the active site. The second was that based on structural identity with ADP-ribosylating toxins, the active site of Tse2 was identified. These results carry the study of this protein forward significantly although the precise function of Tse2 remains unknown. This structure is the first co-structure of a cytotoxic T6SS substrate and has significant implications for the cell in terms of handling the toxin for delivery rather than self intoxication. Advisors/Committee Members: Boraston, Alisdair Bennett (supervisor).

Subjects/Keywords: Structural biology; T6SS; bacteria

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Robb, C. (2015). Structural biology of the type six secretion system. (Thesis). University of Victoria. Retrieved from http://hdl.handle.net/1828/6043

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Robb, Craig. “Structural biology of the type six secretion system.” 2015. Thesis, University of Victoria. Accessed December 07, 2019. http://hdl.handle.net/1828/6043.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Robb, Craig. “Structural biology of the type six secretion system.” 2015. Web. 07 Dec 2019.

Vancouver:

Robb C. Structural biology of the type six secretion system. [Internet] [Thesis]. University of Victoria; 2015. [cited 2019 Dec 07]. Available from: http://hdl.handle.net/1828/6043.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Robb C. Structural biology of the type six secretion system. [Thesis]. University of Victoria; 2015. Available from: http://hdl.handle.net/1828/6043

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universidade do Rio Grande do Norte

2. Medeiros, Viviane Katielly Silva. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .

Degree: 2011, Universidade do Rio Grande do Norte

URL: http://repositorio.ufrn.br/handle/123456789/12642

► Chromobacterium violaceum is a free-living bacillus, Gram-negative commonly found in water and sand of tropical and subtropical regions. One of its main characteristic it's the… (more)

▼ Chromobacterium violaceum is a free-living bacillus, Gram-negative commonly found in water and sand of tropical and subtropical regions. One of its main characteristic it's the ability to produce the purple pigment named violacein, that shows countless biological activities. In 2003, the genome of this organism was totally sequenced and revealed important informations about the physiology of this bacteria. However, few post-genomics studies had been accomplished. This work evaluated the protein profile of C. violaceum cultivated in LB medium at 28ºC that allowed the identification and characterization of proteins related to a possible secretion system that wasn't identified and characterized yet in C. violaceum, to the quorum sensing system, to regulatory process of transcription and translation, stress adaptation and biotechnological potential. Moreover, the response of the bacteria to UVC radiation was evaluated. The comparison of the protein profile, analyzed through 2-D electrophoresis, of the control group versus the treatment group allowed the identification of 52 proteins that arose after stress induction. The obtained results enable the elaboration of a stress response pathway in C. violaceum generated by the UVC light. This pathway, that seems to be a general stress response, involves the expression of proteins related to cellular division, purine and pirimidine metabolism, heat chock or chaperones, energy supply, regulation of biofilm formation, transport, regulation of lytic cycle of bacteriophages, besides proteins that show undefined function. Despite the response present similarities with the classic SOS response of E. coli, we still cannot assert that C. violaceum shows a SOS-like response, mainly due to the absence of characterization of a LexA-like protein in this organism Advisors/Committee Members: Medeiros, Sílvia Regina Batistuzzo de (advisor), CPF:32398336468 (advisor), http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781004Y8 (advisor).

Subjects/Keywords: C. violaceum; UVC; T6SS; proteome; resposta SOS; biofilme; C. violaceum; UVC; T6SS; proteome; SOS response; biofilm

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Medeiros, V. K. S. (2011). Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . (Thesis). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/12642

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Medeiros, Viviane Katielly Silva. “Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .” 2011. Thesis, Universidade do Rio Grande do Norte. Accessed December 07, 2019. http://repositorio.ufrn.br/handle/123456789/12642.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Medeiros, Viviane Katielly Silva. “Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .” 2011. Web. 07 Dec 2019.

Vancouver:

Medeiros VKS. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . [Internet] [Thesis]. Universidade do Rio Grande do Norte; 2011. [cited 2019 Dec 07]. Available from: http://repositorio.ufrn.br/handle/123456789/12642.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Medeiros VKS. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . [Thesis]. Universidade do Rio Grande do Norte; 2011. Available from: http://repositorio.ufrn.br/handle/123456789/12642

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universidade do Rio Grande do Norte

3. Medeiros, Viviane Katielly Silva. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .

Degree: 2011, Universidade do Rio Grande do Norte

URL: http://repositorio.ufrn.br/handle/123456789/12642

► Chromobacterium violaceum is a free-living bacillus, Gram-negative commonly found in water and sand of tropical and subtropical regions. One of its main characteristic it's the… (more)

▼ Chromobacterium violaceum is a free-living bacillus, Gram-negative commonly found in water and sand of tropical and subtropical regions. One of its main characteristic it's the ability to produce the purple pigment named violacein, that shows countless biological activities. In 2003, the genome of this organism was totally sequenced and revealed important informations about the physiology of this bacteria. However, few post-genomics studies had been accomplished. This work evaluated the protein profile of C. violaceum cultivated in LB medium at 28ºC that allowed the identification and characterization of proteins related to a possible secretion system that wasn't identified and characterized yet in C. violaceum, to the quorum sensing system, to regulatory process of transcription and translation, stress adaptation and biotechnological potential. Moreover, the response of the bacteria to UVC radiation was evaluated. The comparison of the protein profile, analyzed through 2-D electrophoresis, of the control group versus the treatment group allowed the identification of 52 proteins that arose after stress induction. The obtained results enable the elaboration of a stress response pathway in C. violaceum generated by the UVC light. This pathway, that seems to be a general stress response, involves the expression of proteins related to cellular division, purine and pirimidine metabolism, heat chock or chaperones, energy supply, regulation of biofilm formation, transport, regulation of lytic cycle of bacteriophages, besides proteins that show undefined function. Despite the response present similarities with the classic SOS response of E. coli, we still cannot assert that C. violaceum shows a SOS-like response, mainly due to the absence of characterization of a LexA-like protein in this organism Advisors/Committee Members: Medeiros, Sílvia Regina Batistuzzo de (advisor), CPF:32398336468 (advisor), http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781004Y8 (advisor).

Subjects/Keywords: C. violaceum; UVC; T6SS; proteome; resposta SOS; biofilme; C. violaceum; UVC; T6SS; proteome; SOS response; biofilm

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Medeiros, V. K. S. (2011). Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . (Doctoral Dissertation). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/12642

Chicago Manual of Style (16^th Edition):

Medeiros, Viviane Katielly Silva. “Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .” 2011. Doctoral Dissertation, Universidade do Rio Grande do Norte. Accessed December 07, 2019. http://repositorio.ufrn.br/handle/123456789/12642.

MLA Handbook (7^th Edition):

Medeiros, Viviane Katielly Silva. “Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC .” 2011. Web. 07 Dec 2019.

Vancouver:

Medeiros VKS. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . [Internet] [Doctoral dissertation]. Universidade do Rio Grande do Norte; 2011. [cited 2019 Dec 07]. Available from: http://repositorio.ufrn.br/handle/123456789/12642.

Council of Science Editors:

Medeiros VKS. Análise proteômica de Chromobacterium violaceum: acúmulo estacionário e diferencial após exposição à luz UVC . [Doctoral Dissertation]. Universidade do Rio Grande do Norte; 2011. Available from: http://repositorio.ufrn.br/handle/123456789/12642

University of Alberta

4. Weber, Brent S. Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii.

Degree: PhD, Department of Biological Sciences, 2016, University of Alberta

URL: https://era.library.ualberta.ca/files/cqf85nb47r

► Antibiotic resistant bacteria that cause hospital-acquired infections are a mounting concern for healthcare systems globally. Multidrug resistant (MDR) Acinetobacter baumannii has emerged as a common… (more)

▼ Antibiotic resistant bacteria that cause hospital-acquired infections are a mounting concern for healthcare systems globally. Multidrug resistant (MDR) Acinetobacter baumannii has emerged as a common cause of nosocomial infections, and some isolates are now pandrug resistant. These infections can be polymicrobial, with one or several other different bacteria being co-isolated with A. baumannii, suggesting interactions with other microorganisms is common for this pathogen. The type VI secretion system (T6SS) has recently been described as an offensive molecular weapon used by many Gram-negative bacteria to kill competing bacteria. This multi-component apparatus facilitates the contact-dependent injection of toxic effector proteins into nearby prey cells and can allow the bacterium expressing the T6SS to dominate a particular environment. Production of cognate immunity proteins prevents self-inflicted intoxication by binding to and inactivating the toxins, which provides a means of discriminating self from non-self. The T6SS is dynamic and energetically costly, and therefore appears to be exquisitely regulated in most bacteria. Apart from increased antibiotic resistance, little is known about the factors that have contributed to the rapid rise of A. baumannii as a nosocomial pathogen. In this thesis, we combined bioinformatic and genetic analyses to experimentally characterize the T6SS in A. baumannii. We found that many species of Acinetobacter secrete a conserved T6SS protein called Hcp, indicating a functional secretory system. Through phenotypic screens and genome sequencing of clinical isolates, we identified a novel regulatory system that controls expression of the T6SS, which confers an anti-bacterial phenotype. This regulatory mechanism resulted in the loss of antibiotic resistance in those cells which activated their T6SS, indicating an incompatibility between these two phenotypes. We found that this regulation was controlled by a conjugative MDR plasmid, with proteins expressed by the plasmid repressing T6SS. We present the hypothesis that A. baumannii differentiate into antibiotic resistant cells or bacterial killers, with the two phenotypes being mutually exclusive. The biogenesis of the T6SS has been intensely studied during the past decade, but has not been investigated in detail for A. baumannii. We screened mutants in the model organism A. baylyi to uncover the genetic requirements for elaborating a functional T6SS. These experiments revealed several essential genes that were required for T6SS function, but had not been characterized in other bacteria. This led to the biochemical characterization of the novel T6SS component TagX, which hydrolyzes peptidoglycan, that we propose facilitates the transit of the T6SS through the producing organism’s peptidoglycan layer. Furthermore, we describe the first T6SS-dependent anti-bacterial effectors of A. baumannii, and elucidate the requirement of VgrG proteins for their effector activity. Overall, the studies presented in this thesis provide a comprehensive…

Subjects/Keywords: Acinetobacter; T6SS; Acinetobacter baumannii; type VI secretion system; anti-bacterial; secretion

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Weber, B. S. (2016). Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii. (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/cqf85nb47r

Chicago Manual of Style (16^th Edition):

Weber, Brent S. “Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii.” 2016. Doctoral Dissertation, University of Alberta. Accessed December 07, 2019. https://era.library.ualberta.ca/files/cqf85nb47r.

MLA Handbook (7^th Edition):

Weber, Brent S. “Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii.” 2016. Web. 07 Dec 2019.

Vancouver:

Weber BS. Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii. [Internet] [Doctoral dissertation]. University of Alberta; 2016. [cited 2019 Dec 07]. Available from: https://era.library.ualberta.ca/files/cqf85nb47r.

Council of Science Editors:

Weber BS. Characterization of the Type VI Secretion System in the Bacterial Pathogen Acinetobacter baumannii. [Doctoral Dissertation]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/cqf85nb47r

Harvard University

5. Ho, Brian Thomas. Characterization of the Antibacterial Activity of the Type VI Secretion System.

Degree: PhD, Biology: Medical Sciences, Division of, 2013, Harvard University

URL: http://nrs.harvard.edu/urn-3:HUL.InstRepos:11745715

► This dissertation summarizes advances made toward understanding of the composition, structure, mechanism, and regulation of the bacterial type VI secretion system (T6SS). The T6SS is… (more)

▼ This dissertation summarizes advances made toward understanding of the composition, structure, mechanism, and regulation of the bacterial type VI secretion system (T6SS). The T6SS is a widely conserved bacterial nanomachine used by Gram-negative bacteria to deliver toxic effector proteins into the extracellular environment or into adjacent target cells. Systematic deletion of open reading frames present in the Vibrio cholerae T6SS gene cluster revealed the genes essential for T6SS activity and provided key insights into understanding the mechanism by which this organelle is assembled and its components are recycled. Characterization of one phage-related T6SS component yielded insight into the mechanism by which many effectors associate with the T6SS organelle and are delivered into target cells. This T6SS component serves both to sharpen the tip of the membrane-puncturing T6SS spike complex and as a vehicle for attaching a diverse set of effector proteins. Time-lapse fluorescence microscopy of GFP-labeled T6SS components revealed key insights into the behavior and regulation of the T6SS in Pseudomonas aeruginosa. The T6SS in this organism assembled in response to exogenous T6SS attack by adjacent sister cells as well as heterologous T6SS+ species V. cholerae and Acinetobacter baylyi. This retaliatory T6SS counterattack was precisely aimed and caused no collateral damage to neighboring, non-aggressive bacteria. These counterattacks are mediated by phosphorylation cascade that recognizes exogenous attacks and post-translationally activates the T6SS in P. aeruginosa. Deletion of genes in this pathway eliminated the retaliatory response while retaining T6SS functionality. This pathway also induced T6SS counterattacks in response to mating pair formation associated with type IV secretion system (T4SS)-mediated DNA conjugation as well as treatment with membrane-disrupting natural product polymyxin B, suggesting that the signal needed to induce T6SS activity was mechanical perturbation of the P. aeruginosa cell membrane. Interestingly, these T4SS-induced counterattacks were able to confer resistance to the acquisition of horizontally transferred foreign DNA by selectively killing conjugative donor cells. As such, the T6SS of P. aeruginosa may represent a type of general bacterial innate immune system capable of responding to a wide range of exogenous threats. Advisors/Committee Members: Mekalanos, John J. (advisor), Goldberg, Marcia (committee member), Lory, Steven (committee member), Collier, John (committee member).

Subjects/Keywords: Microbiology; Molecular biology; Genetics; antimicrobial; bacteria; microbial communication; microbiology; phage; T6SS

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ho, B. T. (2013). Characterization of the Antibacterial Activity of the Type VI Secretion System. (Doctoral Dissertation). Harvard University. Retrieved from http://nrs.harvard.edu/urn-3:HUL.InstRepos:11745715

Chicago Manual of Style (16^th Edition):

Ho, Brian Thomas. “Characterization of the Antibacterial Activity of the Type VI Secretion System.” 2013. Doctoral Dissertation, Harvard University. Accessed December 07, 2019. http://nrs.harvard.edu/urn-3:HUL.InstRepos:11745715.

MLA Handbook (7^th Edition):

Ho, Brian Thomas. “Characterization of the Antibacterial Activity of the Type VI Secretion System.” 2013. Web. 07 Dec 2019.

Vancouver:

Ho BT. Characterization of the Antibacterial Activity of the Type VI Secretion System. [Internet] [Doctoral dissertation]. Harvard University; 2013. [cited 2019 Dec 07]. Available from: http://nrs.harvard.edu/urn-3:HUL.InstRepos:11745715.

Council of Science Editors:

Ho BT. Characterization of the Antibacterial Activity of the Type VI Secretion System. [Doctoral Dissertation]. Harvard University; 2013. Available from: http://nrs.harvard.edu/urn-3:HUL.InstRepos:11745715

University of Washington

6. Corbitt, Jacqueline. T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery.

Degree: PhD, 2017, University of Washington

URL: http://hdl.handle.net/1773/40678

► The Type Six Secretion System (T6SS) is a bacterial toxin-delivery system targeting bacterial cells which neighbor the donor, promoting recipient cell death. The T6SS is… (more)

Subjects/Keywords: fluorescence microscopy; Pseudomonas aeruginosa; T6SS; Biophysics; Microbiology; Applied mathematics; Physics

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Corbitt, J. (2017). T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery. (Doctoral Dissertation). University of Washington. Retrieved from http://hdl.handle.net/1773/40678

Chicago Manual of Style (16^th Edition):

Corbitt, Jacqueline. “T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery.” 2017. Doctoral Dissertation, University of Washington. Accessed December 07, 2019. http://hdl.handle.net/1773/40678.

MLA Handbook (7^th Edition):

Corbitt, Jacqueline. “T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery.” 2017. Web. 07 Dec 2019.

Vancouver:

Corbitt J. T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery. [Internet] [Doctoral dissertation]. University of Washington; 2017. [cited 2019 Dec 07]. Available from: http://hdl.handle.net/1773/40678.

Council of Science Editors:

Corbitt J. T6SS in Pseudomonas aeruginosa: A novel model for toxin delivery. [Doctoral Dissertation]. University of Washington; 2017. Available from: http://hdl.handle.net/1773/40678

7. Nguyen, Van-Son. Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system.

Degree: Docteur es, Biologie, 2016, Aix Marseille Université

URL: http://www.theses.fr/2016AIXM4083

►

Chez les procaryotes, les protéines sont synthétisées dans le cytoplasme avant d'être transportés vers différentes destinations, intra- ou extra-cellulaires. Les bactéries Gram-négatives ont mis au… (more)

▼

Chez les procaryotes, les protéines sont synthétisées dans le cytoplasme avant d'être transportés vers différentes destinations, intra- ou extra-cellulaires. Les bactéries Gram-négatives ont mis au point une grande collection de mécanismes et systèmes, appelés systèmes de sécrétion bactérienne, pour sécréter des protéines à travers leur paroi cellulaire vers l'extérieur. Le système de sécrétion de type VI, identifié dans les années 2006-2008, est une nano-machine polyvalente répandue chez les bactéries pathogènes. Il y a de nombreuses preuves que T6SS injecte des protéines toxiques (effecteurs) directement dans les cellules eucaryotes et procaryotes pour les tuer. Pour empêcher la destruction cellules provenant de la même espèce, les bactéries possédant un T6SS produisent également des protéines d'immunité qui neutralisent les effets toxiques des effecteurs de leurs congénères. Le T6SS est formé de 13 composants de coeur (nommés TssA-M) en une structure souvent comparée à un "bactériophage inversé". La queue, semblable à celle de phages, a une forme tubulaire (la gaine et le tube interne) et polymérise à partir d'une plaque basale ancrée sur un complexe membranaire trans-périplasmique. La contraction de la gaine fournit l'énergie nécessaire pour propulser le tube intérieur à travers la paroi vers les cellules proies. Dans le cadre de ma thèse, je me suis impliqué dans la détermination de la structure et la dynamique de certains composants du T6SS de la d’Escerichia coli enteroaggrégatif (EAEC). Plusieurs structures ont été déterminées et analysées. Quatre articles ont été publiés et deux autres sont en préparation.

In prokaryotes, proteins are synthesized in the cytoplasm before being transported to various destinations, intra- or extra-cellular. Gram-negative bacteria have developed a large collection of mechanisms and systems, termed bacterial secretion systems, to secrete proteins through their cell wall to the exterior. The type VI secretion system, identified in years 2006-2008, is a versatile nano-machine prevalent in pathogenic bacteria. There have been many evidences that T6SS delivers toxic proteins directly into both eukaryotic and prokaryotic cells to kill them. To prevent killing of sibling cells (cells from the same species), T6SS+ cells produce also immunity proteins that neutralize the toxic effects of their cognate effectors. T6SS contains 13 core-components (TssA-M), assembling a structure often quoted as an “inverted bacteriophage”. A phage-like tubular tail (the sheath and the internal tube) polymerizes from a baseplate-like complex, anchored to the cell internal and outer membranes via a membrane anchored complex spanning the periplasm. Contraction of the sheath provides the necessary energy to propel the internal tube through the wall towards the prey cells. In the framework of my PhD, I became involved in determining the structure and dynamics of some components of the EAEC sci1 T6SS, mostly on the membrane and baseplate subcomplexes. Several structures have been determined and analysed. Four…

Advisors/Committee Members: Cambillau, Christian (thesis director), Roussel, Alain (thesis director).

Subjects/Keywords: T6ss; Facteurs de virulence; Eaec; La plaque de base; Complexe membranaire; TssM; TssK; T6ss; Virulence factors; Eaec; Baseplate; Membrane complex; TssM; TssK; 572

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nguyen, V. (2016). Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2016AIXM4083

Chicago Manual of Style (16^th Edition):

Nguyen, Van-Son. “Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system.” 2016. Doctoral Dissertation, Aix Marseille Université. Accessed December 07, 2019. http://www.theses.fr/2016AIXM4083.

MLA Handbook (7^th Edition):

Nguyen, Van-Son. “Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system.” 2016. Web. 07 Dec 2019.

Vancouver:

Nguyen V. Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system. [Internet] [Doctoral dissertation]. Aix Marseille Université 2016. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2016AIXM4083.

Council of Science Editors:

Nguyen V. Caractérisation structurale de la partie trans-périplasmique et de la plaque de base du système de sécrétion de type VI de EAEC 042 sci1 : Structural characterisation of trans-periplasm and baseplate components from the EAEC 042 sci1 type VI secretion system. [Doctoral Dissertation]. Aix Marseille Université 2016. Available from: http://www.theses.fr/2016AIXM4083

Universidade do Rio Grande do Sul

8. Oliveira, Aline Luísa de. Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC).

Degree: 2015, Universidade do Rio Grande do Sul

URL: http://hdl.handle.net/10183/119612

►

Escherichia coli patogênicas aviárias (APEC) causam infecções extraintestinais em aves, que podem ser localizadas ou sistêmicas, denominadas colibacilose. O patotipo de APEC não está definido,… (more)

▼

Escherichia coli patogênicas aviárias (APEC) causam infecções extraintestinais em aves, que podem ser localizadas ou sistêmicas, denominadas colibacilose. O patotipo de APEC não está definido, mas vários genes de virulência são associados a essas cepas, como os genes plasmidiais iroN, ompT, hlyF, iss e iutA, propostos, em 2008, como preditores da virulência de APEC. Além dos genes de virulência conhecidos, outros fatores podem estar associados à patogenicidade bacteriana, como as maquinarias de secreção protéica denominadas Sistemas de Secreção. O Sistema de Secreção do Tipo 6 (T6SS), descrito em 2006, tem sido associado à virulência de cepas APEC. Este trabalho divide-se em duas partes: a primeira teve como objetivo avaliar a frequência dos genes iroN, ompT, hlyF, iss e iutA em 401 cepas aviárias de E. coli e sua relação com a patogenicidade in vivo dessas cepas. A segunda parte teve como objetivos verificar a frequência de genes componentes do T6SS (clpV, vgrG, icmF e dotU), em uma coleção de 187 cepas APEC; e, em algumas cepas positivas para os genes, verificar a expressão de um fenótipo relacionado ao sistema, bem como a expressão do efetor vgrG e da ATPase do sistema clpV2, além da secreção de proteínas, no meio de cultura e durante contato com células eucarióticas. Os resultados da primeira parte indicam que cepas com dois ou mais dos genes analisados tem maior probabilidade de serem patogênicas do que cepas com apenas um ou nenhum dos genes. Já os da segunda parte mostram que várias cepas apresentaram duas cópias de pelo menos um dos genes testados, e algumas delas apresentaram resistência à predação por D. discoideum. Não foram encontradas diferenças entre a expressão dos genes vgrG (1 e 2) e clpV2 em cultura pura ou em contato com células eucarióticas. Este trabalho apresenta a triagem de genes plasmidiais em uma grande coleção de amostras de Escherichia coli, e a primeira triagem de genes do T6SS em uma coleção de isolados APEC.

Avian pathogenic Escherichia coli (APEC) causes extraintestinal infections in birds, which can be localized or systemic, known as colibacillosis. The APEC pathotype is still undefined, but several virulence genes are associated with these strains, as the plasmid-linked genes iroN, ompT, hlyF, iss and iutA, proposed in 2008 as APEC virulence predictors. Besides the known virulence genes, other factors may be associated with bacterial pathogenicity, such as the protein secretion machineries called Secretion Systems. Described in 2006, Type 6 Secretion System (T6SS) has been associated with virulence of APEC strains. This work is divided in two parts: the first aimed to evaluate the frequency of iroN, ompT, hlyF, iss and iutA genes in 401 avian strains of E. coli and its relationship with in vivo pathogenicity of these strains. The second part aimed to verify the frequency of T6SS genes (clpV, vgrG, icmF and dotU) in a collection of 187 APEC strains; and verify, in some positive strains, the expression of a phenotype related to the system, as well as the gene expression of effector…

Advisors/Committee Members: Horn, Fabiana.

Subjects/Keywords: APEC; Colibacilose; Colibacillosis; Escherichia coli patogênica aviária; Patogenicidade; Plasmid-linked genes; Genes; T6SS; Pathogenicity

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Oliveira, A. L. d. (2015). Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC). (Thesis). Universidade do Rio Grande do Sul. Retrieved from http://hdl.handle.net/10183/119612

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Oliveira, Aline Luísa de. “Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC).” 2015. Thesis, Universidade do Rio Grande do Sul. Accessed December 07, 2019. http://hdl.handle.net/10183/119612.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Oliveira, Aline Luísa de. “Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC).” 2015. Web. 07 Dec 2019.

Vancouver:

Oliveira ALd. Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC). [Internet] [Thesis]. Universidade do Rio Grande do Sul; 2015. [cited 2019 Dec 07]. Available from: http://hdl.handle.net/10183/119612.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Oliveira ALd. Relação entre genes plasmidiais e virulência e análise do sistema de secreção tipo 6 em isolados de Escherichia coli patogênica aviária (APEC). [Thesis]. Universidade do Rio Grande do Sul; 2015. Available from: http://hdl.handle.net/10183/119612

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

9. Brunet, Yannick. Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail.

Degree: Docteur es, Microbiologie, 2013, Aix Marseille Université

URL: http://www.theses.fr/2013AIXM4032

►

Résumé : La compréhension des contraintes qui régissent l'assemblage des machineries supramoléculaires – qu'elles soient solubles ou bien ancrées dans les membranes biologiques – est… (more)

▼

Résumé : La compréhension des contraintes qui régissent l'assemblage des machineries supramoléculaires – qu'elles soient solubles ou bien ancrées dans les membranes biologiques – est un enjeu scientifique majeur.Le système de de sécrétion type VI (T6SS) est un organelle bactérien récemment mis en évidence qui a pour particularité de posséder une origine évolutive commune avec le bactériophage T4. En raison de cette origine évolutive commune, certaines sous unités du T6SS et du bactériophage T4 présentent des structures comparables. Cependant, un grand nombre des sous unités du T6SS reste à caractériser. Parmi celles-ci, les protéines SciB et SciC sont retrouvées dans tous les systèmes de sécrétion de type VI suggérant que ces deux protéines participent à la formation du "core-complexe": le complexe minimal requis pour le fonctionnement du T6SS.

The recently identified type VI secretion system has been demonstrated to be involved in most of these processes. The T6SS is a highly complex macromolecular machine that allows Gram-negative bacteria to deliver effector proteins to both prokaryotic and eukaryotic cells in a contact-dependent manner. The T6SS promotes therefore antibacterial competition, virulence towards eukaryotes or even both. The T6SS is composed of a minimal set of 13 subunits, which are currently believed to form the core apparatus. They assemble two distinct sub-complexes: one is a cytosolic contractile structure related to the tail of contractile bacteriophages, whereas the other spans the whole cell envelope. Therefore, the T6SS is generally depicted as an inverted phage tail anchored to the cell envelope through its membrane-associated complex. Contractile tails are currently thought to assemble from four structural elements: the baseplate, the internal tube, the contractile sheath and the tail terminator. The aim of my Ph.D. work was to further characterize the assembly and function of the T6SS phage tail-like complex in enteroaggregative E. coli. In this thesis document, I provide evidence that the internal tube assembles from Hcp hexamers stacked in a head-to-tail manner and that this internal cylinder is used as a template during sheath assembly. I also characterized a sub-complex of three proteins (TssEFG) that forms the baseplate of the T6SS and controls the polymerization of the tube and sheath. Finally, I recently showed that the T6SS functions like a nano-crossbow to kill target cells as the contraction of the T6SS results in prey cell death during interbacterial competition.

Advisors/Committee Members: Cascales, Eric (thesis director).

Subjects/Keywords: SST6; Compétition interbactérienne; Bactériophages; Plateforme d'assemblage; Microscope fluorescent; T6SS; Inyterbacterial competition; Contractile bacteriophages; Assembly baseplate; Fluorescence microscopy; 579

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Brunet, Y. (2013). Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2013AIXM4032

Chicago Manual of Style (16^th Edition):

Brunet, Yannick. “Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail.” 2013. Doctoral Dissertation, Aix Marseille Université. Accessed December 07, 2019. http://www.theses.fr/2013AIXM4032.

MLA Handbook (7^th Edition):

Brunet, Yannick. “Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail.” 2013. Web. 07 Dec 2019.

Vancouver:

Brunet Y. Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail. [Internet] [Doctoral dissertation]. Aix Marseille Université 2013. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2013AIXM4032.

Council of Science Editors:

Brunet Y. Caractérisation moléculaire du systeme de secrétion de type VI d'escherichia coli enteroagrégatif et de ses mécanismes de régulation . : Structure and function of the type vi secretion system tail. [Doctoral Dissertation]. Aix Marseille Université 2013. Available from: http://www.theses.fr/2013AIXM4032

10. Sana, Thibault. Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides.

Degree: Docteur es, Microbiologie, 2013, Aix Marseille Université

URL: http://www.theses.fr/2013AIXM4027

►

Pseudomonas aeruginosa est une bactérie pathogène opportuniste extracellulaire. La souche PAO1 de P. aeruginosa possède trois loci codant des Systèmes de Sécrétion de Type VI… (more)

▼

Pseudomonas aeruginosa est une bactérie pathogène opportuniste extracellulaire. La souche PAO1 de P. aeruginosa possède trois loci codant des Systèmes de Sécrétion de Type VI (T6SS) indépendants, nommés H1 à H3-T6SS. Le premier d'entre eux, H1-T6SS, a été largement décrit dans la littérature scientifique et injecte des toxines à activité antiprocaryote dans d'autres bactéries permettant une défense active contre l'attaque d'un T6SS d'une autre bactérie. Les deux autres T6SS de P. aeruginosa sont probablement des facteurs de virulence de cette bactérie, mais aucun effecteur sécrété, ni cible intracellulaire ou rôle n'ont été proposés jusqu'ici. Dans ce travail de thèse, nous avons mis en évidence que la machinerie H2-T6SS permet l'invasion de cellules non-phagocytaires et participe à la virulence de P. aeruginosa. Cette entrée requière la dynamique du réseau de microtubules, via VgrG2b injectée par la machinerie H2-T6SS dans les cellules épithéliales, et capable de cibler les complexes de gamma-tubulines, centre nucléateur des microtubules. Il s'agit d'un mécanisme d'internalisation tout à fait original et jamais encore décrit. Nous avons également exploré la régulation croisée entre H2 et H3-T6SS. Enfin par une analyse de « RNAseq », nous avons observé entre les souches PAO1 et PA14 de P. aeruginosa une expression différentielle de nombreux gènes, certains codant des facteurs de virulence. Pour près de 30% d'entre eux, l'origine de cette variation reposerait sur une quasi-absence d'expression dans la souche PA14 de qslA, codant un anti-activateur du Quorum-Sensing. Ceci serait une nouvelle explication du phénotype hyper-virulent de la souche PA14 de P. aeruginosa.

Pseudomonas aeruginosa is an opportunistic extracellular pathogen. The PAO1 strain of P. aeruginosa harbors three loci encoding independent Type VI Secretion Systems (T6SS), named H1 to H3-T6SS. H1-T6SS has been widely described in the literature and injects toxins with antiprokaryotic activity in target bacteria, allowing an active defense against the attack of a T6SS from another bacterium. The other two T6SS of P. aeruginosa are likely virulence factors, but no secreted effector or intracellular target or role have been proposed so far.In this work, we demonstrated that the H2-T6SS machinery triggered the invasion of non-phagocytic epithelial cells and is involved in the virulence of P. aeruginosa. This uptake is mediated by the microtubule network dynamics, and via VgrG2b, injected by the H2-T6SS machinery in epithelial cells, to target the gamma-tubulin complex, the microtubule nucleating center. This is an original mechanism of internalization never described before. We also studied the cross-regulation between H2 and H3-T6SS. Finally through a « RNAseq » analysis, we observed differential expression of many genes, including some encoding virulence factors, between PAO1 and PA14 strains of P. aeruginosa. For nearly 30% of them, the origin of this variation is an almost lack of expression in the PA14 strain of qslA, encoding an anti-Quorum Sensing…

Advisors/Committee Members: Bleves, Sophie (thesis director).

Subjects/Keywords: Pseudomonas aeruginosa; SST6; Internalisation; Quorum-sensing; Fur; Virulence; Régulation; RpoN; EBP; QslA; Pseudomonas aeruginosa; T6SS; Internalization; Quorum-sensing; Fur; Virulence; Regulation; RpoN; EBP; QslA; 579

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sana, T. (2013). Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2013AIXM4027

Chicago Manual of Style (16^th Edition):

Sana, Thibault. “Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides.” 2013. Doctoral Dissertation, Aix Marseille Université. Accessed December 07, 2019. http://www.theses.fr/2013AIXM4027.

MLA Handbook (7^th Edition):

Sana, Thibault. “Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides.” 2013. Web. 07 Dec 2019.

Vancouver:

Sana T. Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides. [Internet] [Doctoral dissertation]. Aix Marseille Université 2013. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2013AIXM4027.

Council of Science Editors:

Sana T. Caractérisation de deux systèmes de sécrétion de type VI de Pseudomonas aeruginosa : Cross-régulation et rôle dans l'invasion microtubules-dépendante de cellules non-phagocytaires : Synthèse, études cristallographiques et magnétiques d'édifices moléculaires à base de lanthanides. [Doctoral Dissertation]. Aix Marseille Université 2013. Available from: http://www.theses.fr/2013AIXM4027

Université de Grenoble

11. Sall, Khady. Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate.

Degree: Docteur es, Virologie, Microbiologie, Immunologie, 2013, Université de Grenoble

URL: http://www.theses.fr/2013GRENV051

►

Pseudomonas aeruginosa est un bacille gram négatif, ubiquiste de l'environnement. Ce pathogène opportuniste humain provoque sous sa forme planctonique des infections aiguës dont le facteur… (more)

▼

Pseudomonas aeruginosa est un bacille gram négatif, ubiquiste de l'environnement. Ce pathogène opportuniste humain provoque sous sa forme planctonique des infections aiguës dont le facteur de virulence clé est le SST3. P. aeruginosa peut aussi se développer sous forme de biofilm où elle exprime entre autre le SST6-1 et induire des infections chroniques. L'expression ciblée des différents facteurs de virulence est liée à l'intégration de nombreux stimuli environnementaux transduits au moyen de systèmes à deux composants ou encore de messagers secondaires, comme le di-GMPc et l'AMPc, et conduisant à une régulation très fine, conférant une grande capacité d'adaptation à la bactérie. La nature, de même que les mécanismes impliqués dans la transduction du signal, n'ont pas encore été tous identifiés à ce jour. Le but de cette thèse était de décrypter ces mécanismes moléculaires de détection et de transduction du signal gouvernant la réponse adaptative de ce pathogène à son environnement au moyen de différentes approches : chémogénomique, mutagénèse aléatoire et d'étude d'isolat clinique. Lors de cette thèse, nous avons criblé deux chimiothèques commerciales à la recherche de molécules activatrices du SST3 et du SST6-1 et nous avons pu établir un test de criblage à haut débit robuste pour les criblages de plus larges banques de composés. En utilisant une souche avec deux rapporteurs, nous avons réalisé une banque de mutants par transposons et nous avons trouvé des mutants affectés dans leur expression du SST3, candidats intéressants pour identifier de nouveaux régulateurs du système. Enfin, grâce à l'analyse de l'isolat clinique CHA (issu d'un patient atteint de mucoviscidose), nous avons découvert qu'une délétion dans le gène codant pour le régulateur majeur GacS définissait le phénotype agressif de cette souche.

Pseudomonas aeruginosa is a gram negative bacillum present in several places. This opportunistic pathogen has the capacity to infect a wide range of hosts: plants, animals, humans. This bacterium, that shows an impressive adaptability relying on a multifactorial virulence, possesses two lifestyles. These lifestyles are associated with specific virulence patterns of expression. Under its planktonic form, P. aeruginosa can provoke acute infections thanks to the activation of T2 and T3SS or induces chronic infections in cystic fibrosis patients' lungs where it establishes a biofilm (communautary life). The expression of virulence factors is linked to the integration of several environmental cues that are transduced through two-component systems and secondary messengers like c-di-GMP and that lead to a fine tuned regulation. The nature and the mechanisms involved in this signal transduction remain largely unknown. The goal of this thesis was to decipher molecular mechanisms of signal detection and transduction that govern the adaptive pathogen response to host environment using the combination of a chemogenomics, random mutagenesis and study of clinical isolate. During this work, we screened two commercial…

Advisors/Committee Members: Elsen, Sylvie (thesis director).

Subjects/Keywords: Pseudomonas aeruginosa; Régulation; Criblage à haut débit; Mucoviscidose; SST3; SST6-1; Pseudomonas aeruginosa; Regulation; High throughput screening; Cystic fibrosis; T3SS; T6SS-1; 570

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sall, K. (2013). Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate. (Doctoral Dissertation). Université de Grenoble. Retrieved from http://www.theses.fr/2013GRENV051

Chicago Manual of Style (16^th Edition):

Sall, Khady. “Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate.” 2013. Doctoral Dissertation, Université de Grenoble. Accessed December 07, 2019. http://www.theses.fr/2013GRENV051.

MLA Handbook (7^th Edition):

Sall, Khady. “Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate.” 2013. Web. 07 Dec 2019.

Vancouver:

Sall K. Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate. [Internet] [Doctoral dissertation]. Université de Grenoble; 2013. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2013GRENV051.

Council of Science Editors:

Sall K. Etude de la régulation du système de sécrétion de type 3 et du système de sécrétion de type 6 chez Pseudomonas aeruginosa : Approches de chémogénomique, mutagénèse aléatoire et étude d'isolat clinique : Study of the regulation of the Type III and Type VI Secretion Systems in Pseudomonas aeruginosa : Chemogenomic approaches, random mutagenesis and study of clinical isolate. [Doctoral Dissertation]. Université de Grenoble; 2013. Available from: http://www.theses.fr/2013GRENV051

Université de Grenoble

12. Casabona, Maria Guillermina. Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa.

Degree: Docteur es, Médecine, 2013, Université de Grenoble

URL: http://www.theses.fr/2013GRENV009

►

La bactérie à Gram-négatif Pseudomonas aeruginosa est un pathogène humain opportuniste qui peut causer des infections chroniques pouvant conduire à la mort des patients, et… (more)

▼

La bactérie à Gram-négatif Pseudomonas aeruginosa est un pathogène humain opportuniste qui peut causer des infections chroniques pouvant conduire à la mort des patients, et plus particulièrement ceux atteints de la mucoviscidose. Il a été montré qu‘un de ses trois systèmes de sécrétion de type VI (SST6) est actif durant les infections chroniques, le SST6-H1. P. aeruginosa est capable d'injecter des toxines de type bactériolytique directement dans le périplasme des autres bactéries à Gram-négatif grâce au SST6-H1, ce qui laisse penser que cette nanomachine pourrait être capitale dans la compétitivité de P. aeruginosa dans les niches polymicrobiennes, comme par exemple un poumon infecté. Cette nanomachine insérée dans l'enveloppe bactérienne est régulée au niveau post-traductionnel par une voie de phosphorylation ressemblant à celles des eucaryotes. Cette voie est constituée par une kinase, PpkA, et une phosphatase, PppA, qui modulent ensemble le niveau de phosphorylation de la protéine Fha1. Nous avons démontré que quatre protéines spécifiques de Pseudomonas appelées TagT, TagS, TagR et TagQ, agissent en amont du couple PpkA/PppA, et sont indispensables pour l'activation du SST6-H1. De plus, elles sont aussi nécessaires lors de compétitions entre P. aeruginosa et d'autres bactéries. Nous avons montré que TagR, connue comme étant une protéine périplasmique, est en fait associée à la membrane externe et cette localisation dépend de TagQ, une lipoprotéine ancrée dans le feuillet interne de la membrane externe. TagT et TagS forment un transporteur de type ABC qui a une activité d'ATPase. L'association de TagR à la membrane externe a été mise en évidence par des études de protéomique à haut débit qui avaient pour but la caractérisation des membranes externe et interne de P. aeruginosa. Grâce à l'analyse des résultats, unmodèle de l'assemblage du SST6-H1 au sein de l'enveloppe a pu être proposé. Ce travail a permis l'identification de plus de 1700 protéines, parmi elles un complexe multi-protéique incluant MagD, une protéine homologue à la macroglobuline humaine. Les résultats obtenus lors de la caractérisation de ce complexe sont aussi présentés dans ce manuscrit.

Pseudomonas aeruginosa is a human opportunistic pathogen that can cause severe infections and death in chronically infected cystic fibrosis (CF) patients. It has been shown that one of its three Type VI Secretion Systems (T6SS), the H1-T6SS, is active during chronic infections in CF patients. P. aeruginosa injects bacteriolytic toxins directly into other Gram-negative bacteria by means of its H1-T6SS, which could be of high importance in its outcome in complex niches such as an infected lung. This trans-envelope nanomachine is posttranslationally regulated by a eukaryotic-like phosphorylation pathway, which includes a kinase-phosphatase pair, PpkA and PppA, respectively. In this work, TagT, TagS, TagR and TagQ, Pseudomonas specific T6SS proteins that are encoded in the same operon as Ppka, PppA and Fha1, were analysed functionally and biochemically. We found…

Advisors/Committee Members: Attree-Delic, Ina (thesis director).

Subjects/Keywords: Pseudomonas aeruginosa; SST6; Régulation post-traductionnelle; Protéomique à haut débit; Sous-protéome; Pseudomonas aeruginosa; T6SS; Posttranslational regulation; Shotgun proteomics; IM-OM sub-proteomes

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Casabona, M. G. (2013). Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa. (Doctoral Dissertation). Université de Grenoble. Retrieved from http://www.theses.fr/2013GRENV009

Chicago Manual of Style (16^th Edition):

Casabona, Maria Guillermina. “Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa.” 2013. Doctoral Dissertation, Université de Grenoble. Accessed December 07, 2019. http://www.theses.fr/2013GRENV009.

MLA Handbook (7^th Edition):

Casabona, Maria Guillermina. “Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa.” 2013. Web. 07 Dec 2019.

Vancouver:

Casabona MG. Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa. [Internet] [Doctoral dissertation]. Université de Grenoble; 2013. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2013GRENV009.

Council of Science Editors:

Casabona MG. Mécanismes moléculaires impliqués dans la régulation post-traductionnelle du système de sécrétion du type VI chez Pseudomonas aeruginosa : Molecular mechanisms involved in the post-translational regulation of type VI secretion system in Pseudomonas aeruginosa. [Doctoral Dissertation]. Université de Grenoble; 2013. Available from: http://www.theses.fr/2013GRENV009

13. Gallique, Mathias. Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition.

Degree: Docteur es, Aspects moleculaires et cellulaires de la biologie, 2017, Normandie

URL: http://www.theses.fr/2017NORMR087

►

Le système de sécrétion de type VI (SST6) est un complexe multi-protéique permettant l’export d’effecteurs. Ce mécanisme est impliqué à la fois dans la virulence… (more)

▼

Le système de sécrétion de type VI (SST6) est un complexe multi-protéique permettant l’export d’effecteurs. Ce mécanisme est impliqué à la fois dans la virulence envers les cellules eucaryotes, dans l’activité antibactérienne mais également dans l’acquisition d’ions présents dans ’environnement. Ainsi, le SST6 joue un rôle important dans l’adaptation et la compétition, éléments essentiels dans la colonisation et la persistance au sein d’une niche écologique. Actuellement, très peu d’études portent sur l’importance du SST6 chez des souches environnementales, contrairement aux nombreuses études portant sur des pathogènes tels que Pseudomonas aeruginosa, Burkholderia thailandensis, Vibrio cholerae ou Escherichia coli. Mon sujet de recherche avait pour objectif de caractériser le ou les rôles du SST6 de la souche environnementale Pseudomonas fluorescens MFE01. Ces travaux ont permis d’appréhender certaines fonctions du SST6 de cette souche. Le génome de MFE01 ne comporte qu’un seul cluster de gènes du SST6 où sont regroupés les gènes codant pour la machinerie du SST6 (le « core-component ») à l’exception des gènes hcp. Les protéines Hcp sont des éléments structuraux du SST6 dont elles forment le tube interne qui permet le transfert des effecteurs. Différents gènes hcp sont disséminés sur le chromosome et parmi ces « hcp » orphelins, hcp2 et hcp3 codent respectivement pour les protéines Hcp2 et Hcp3. Ces deux Hcp sécrétées par le SST6, sont associées à l’activité antibactérienne de MFE01 sur différentes souches pathogènes et environnementales, tels que P. aeruginosa, P. fluorescens MFN1032 et Pectobacterium atrosepticum. La protéine Hcp1, codée par le gène orphelin hcp1, est impliquée dans l’inhibition de mobilité de souche compétitrice. Hcp1 permettrait la sécrétion d’au moins deux toxines qui perturberaient l’assemblage du flagelle. Chez MFE01Δhcp1 et MFE01ΔtssC (TssC est un élément de la gaine contractile du SST6), ces toxines seraient accumulées dans le cytoplasme, inhibant ainsi ’assemblage de leur propre flagelle. La surproduction du régulateur FliA, qui contrôle notamment l’assemblage du filament flagellaire, restaure la mobilité chez ces deux mutants. En parallèle, le SST6 de la souche MFE01 est essentiel à la formation et la maturation de biofilm mais également à la compétition bactérienne en biofilm mixte. Ce système interviendrait dans la communication bactérienne indispensable au comportement social, requis lors de l’élaboration des biofilms.

Type VI secretion system (T6SS) is a multiproteic apparatus that secreted proteinaceous effectors. T6SS participate in a variety of functions, whose eukaryote virulence, antibacterial activity or metal ion uptake. These capacities conferring an advantage in adaptation and competition, crucial to colonization or persistence within ecological niche. As well, only a few studies have focused on the T6SS functions of environmental strains, contrary to numerous studies dealing with pathogens as Pseudomonas aeruginosa, Burkholderia thailandensis, Vibrio cholerae or…

Advisors/Committee Members: Merieau, Annabelle (thesis director).

Subjects/Keywords: Système de sécrétion de type VI (SST6); Pseudomonas fluorescens; Biofilm; Flagelle; Compétition bactérienne; Activité antibactérienne; Type VI secretion system (T6SS); Pseudomonas fluorescens; Biofilm; Flagella; Antibacterial activity; 579.3

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gallique, M. (2017). Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition. (Doctoral Dissertation). Normandie. Retrieved from http://www.theses.fr/2017NORMR087

Chicago Manual of Style (16^th Edition):

Gallique, Mathias. “Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition.” 2017. Doctoral Dissertation, Normandie. Accessed December 07, 2019. http://www.theses.fr/2017NORMR087.

MLA Handbook (7^th Edition):

Gallique, Mathias. “Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition.” 2017. Web. 07 Dec 2019.

Vancouver:

Gallique M. Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition. [Internet] [Doctoral dissertation]. Normandie; 2017. [cited 2019 Dec 07]. Available from: http://www.theses.fr/2017NORMR087.

Council of Science Editors:

Gallique M. Implication du système de sécrétion de type VI de la souche Pseudomonas fluorescens MFE01 dans l'activité antibactérienne, la formation de biofilm et l'inhibition de mobilité. : Involvement of Pseudomonas fluorescens type VI secretion system on antibacterial activity, biofilm formation and motility inhibition. [Doctoral Dissertation]. Normandie; 2017. Available from: http://www.theses.fr/2017NORMR087

14. Russell, Alistair Brian. Antibacterial effectors of the type VI secretion system.

Degree: PhD, 2014, University of Washington

URL: http://hdl.handle.net/1773/26078

► With the advent of high-throughput culture-independent sequencing it has become increasingly apparent that bacteria often live in complex communities, both in the environment and in… (more)

▼ With the advent of high-throughput culture-independent sequencing it has become increasingly apparent that bacteria often live in complex communities, both in the environment and in association with the human body. Moreover, in polymicrobial settings there is often fierce competition for both space and resources, the results of which can have drastic effects on community composition. The evolutionary pressure exerted by competition is reflected by the significant portion of the coding capacity of many bacterial genomes dedicated to the production and regulation of antagonistic pathways. One such pathway, the type VI secretion system (T6SS), has emerged as a mechanism mediating the delivery of potent antibacterial effectors between contacting Gram-negative bacteria, granting the attacking organism a fitness benefit over sensitive neighbors. Initial studies of interbacterial T6S provided evidence that this system plays an important role in antagonism, however its mechanism of action on recipient cells remained elusive. This thesis describes the first biochemical characterization of antibacterial T6SS effector proteins, finding that they compromise basal features of bacterial physiology such as cell envelope integrity. By targeting highly conserved processes the T6SS has the capacity to mediate antagonism between highly disparate organisms. The cost of such versatility is that bacteria are susceptible to their own T6SS effectors. In order to overcome this hurdle antibacterial effectors are invariably associated with cognate immunity proteins that prevent their toxicity, protecting the producing cell. Beyond initial biochemical characterization of antibacterial effector proteins, this work describes informatic efforts to identify substrates secreted by the interbacterial T6SS throughout sequenced bacterial genomes. This strategy uncovered highly divergent effector sequences comprising distinct families within superfamilies defined by a common enzymatic target. These divergent effectors not only exhibit distinct substrate specificities, but also vary in their capacity to be neutralized by different sets of immunity proteins. Lastly, our informatic efforts led to the discovery of antibacterial effector proteins in a phylum of Gram-negative bacteria not predicted to encode a T6SS, the Bacteroidetes. My work on this abundant environmental and human-associated phylum of bacteria has found that they possess a highly divergent T6S-like pathway, one that, like its Proteobacterial homolog, takes part in interbacterial antagonism. Together, these findings represent a significant advancement in the field of interbacterial T6S, and serve as a platform for further work defining the in situ benefit of this antagonistic pathway. Advisors/Committee Members: Mougous, Joseph D (advisor).

Subjects/Keywords: antagonism; bactera; Bacteroidetes; peptidoglycan; phospholipase; T6SS; Microbiology; microbiology

…secretion system (T6SS) (1-5). Originally identified as a cluster of conserved… …appreciated that the thirteen elements conserved between Proteobacterial T6SS-gene clusters define… …the T6SS demonstrated that in a few organisms it, like the T3SS or T4SS, could target… …made with the observation that a T6SS encoded by the organism Pseudomonas aeruginosa could be… …The paradigm defined by these two proteins has revolutionized the study of the T6SS as 2…

2 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Russell, A. B. (2014). Antibacterial effectors of the type VI secretion system. (Doctoral Dissertation). University of Washington. Retrieved from http://hdl.handle.net/1773/26078

Chicago Manual of Style (16^th Edition):

Russell, Alistair Brian. “Antibacterial effectors of the type VI secretion system.” 2014. Doctoral Dissertation, University of Washington. Accessed December 07, 2019. http://hdl.handle.net/1773/26078.

MLA Handbook (7^th Edition):

Russell, Alistair Brian. “Antibacterial effectors of the type VI secretion system.” 2014. Web. 07 Dec 2019.

Vancouver:

Russell AB. Antibacterial effectors of the type VI secretion system. [Internet] [Doctoral dissertation]. University of Washington; 2014. [cited 2019 Dec 07]. Available from: http://hdl.handle.net/1773/26078.

Council of Science Editors:

Russell AB. Antibacterial effectors of the type VI secretion system. [Doctoral Dissertation]. University of Washington; 2014. Available from: http://hdl.handle.net/1773/26078

15. HU WENTAO. MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA.

Degree: 2013, National University of Singapore

URL: http://scholarbank.nus.edu.sg/handle/10635/37804

Subjects/Keywords: EvpP; T6SS; E. tarda; limited proteolysis; 4D NMR; HDX-MS

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

WENTAO, H. (2013). MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA. (Thesis). National University of Singapore. Retrieved from http://scholarbank.nus.edu.sg/handle/10635/37804

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

WENTAO, HU. “MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA.” 2013. Thesis, National University of Singapore. Accessed December 07, 2019. http://scholarbank.nus.edu.sg/handle/10635/37804.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

WENTAO, HU. “MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA.” 2013. Web. 07 Dec 2019.

Vancouver:

WENTAO H. MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA. [Internet] [Thesis]. National University of Singapore; 2013. [cited 2019 Dec 07]. Available from: http://scholarbank.nus.edu.sg/handle/10635/37804.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

WENTAO H. MAPPING THE RIGID AND FLEXIBLE REGIONS OF A NOVEL SECRETED PROTEIN EVPP FROM THE T6SS OF EDWARDSIELLA TARDA. [Thesis]. National University of Singapore; 2013. Available from: http://scholarbank.nus.edu.sg/handle/10635/37804

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Florida

16. Joseph, Jennifer. The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus.

Degree: PhD, Medical Sciences - Immunology and Microbiology (IDP), 2009, University of Florida

URL: http://ufdc.ufl.edu/UFE0041220

► Vibrio vulnificus is a gram-negative bacterium capable of causing serious infections after ingestion of contaminated seafood or contact of wounds with contaminated water or objects.… (more)

▼ Vibrio vulnificus is a gram-negative bacterium capable of causing serious infections after ingestion of contaminated seafood or contact of wounds with contaminated water or objects. The bacteria are highly cytotoxic to host cells and cause extensive tissue damage during infection. The factors involved in this damage remain unknown. The focus of this investigation was to examine the role of toxins and other secreted factors of V. vulnificus in virulence and cytotoxicity. We examined the Repeats in Toxin (RTX) toxins and proteins secreted via the type VI secretion system (T6SS) by constructing mutations in V. vulnificus and evaluating their effects on virulence in mice and cytotoxicity in cell culture models. V. vulnificus encodes three RTX toxins, RtxA1, RtxA2, and RtxA3. We examined all three toxins and their activation by RtxC. rtxA1 mutants were defective in cytotoxicity to intestinal epithelial INT-407 cells and the ability to induce apoptosis in J774 murine macrophage-like cells. rtxA1 mutants were also attenuated for virulence in subcutaneously inoculated, iron dextran-treated mice; however, they were still able to cause subcutaneous lesions similar to the wild type, suggesting that other virulence factors cause these lesions. Additionally, RtxA1 does not require activation by RtxC for virulence or cytotoxicity. Deletion of either rtxA2 or rtxA3 had no significant effect on cytotoxicity in cell culture or virulence in mice. The recently discovered T6SS was examined for its role in cytotoxicity and virulence. The hemolysin coregulated protein (HCP) and Valine-glycine repeat protein (VgrG) are suggested to be secreted effectors and components of the T6SS apparatus. Deletion of each of these genes in V. vulnificus had no effect on cytotoxicity in cell culture or virulence in mice, suggesting that the T6SS is not essential in virulence and tissue damage caused by V. vulnificus. These studies evaluated several toxins and secreted factors of V. vulnificus for cytotoxicity and virulence. We identified RtxA1 as the major cytotoxic factor; however, other accessory toxins contribute to cytotoxicity. Despite examining several toxins and identifying the major cytotoxic factor, the key factor(s) involved in tissue damage remains elusive. ( en ) Advisors/Committee Members: Gulig, Paul A. (committee chair), Jin, Shouguang (committee member), Baker, Henry V. (committee member), Wright, Anita C. (committee member).

Subjects/Keywords: Apoptosis; Bacteria; Cytotoxicity; Genetic mutation; Infections; Lesions; Skin; Toxins; Vibrio vulnificus; Virulence; pathogenesis, rtx, secretion, system, t6ss, toxins, type, vi, vibrio, vulnificus

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Joseph, J. (2009). The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus. (Doctoral Dissertation). University of Florida. Retrieved from http://ufdc.ufl.edu/UFE0041220

Chicago Manual of Style (16^th Edition):

Joseph, Jennifer. “The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus.” 2009. Doctoral Dissertation, University of Florida. Accessed December 07, 2019. http://ufdc.ufl.edu/UFE0041220.

MLA Handbook (7^th Edition):

Joseph, Jennifer. “The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus.” 2009. Web. 07 Dec 2019.

Vancouver:

Joseph J. The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus. [Internet] [Doctoral dissertation]. University of Florida; 2009. [cited 2019 Dec 07]. Available from: http://ufdc.ufl.edu/UFE0041220.

Council of Science Editors:

Joseph J. The Role of Toxins and Secreted Factors in the Pathogenesis of Vibrio vulnificus. [Doctoral Dissertation]. University of Florida; 2009. Available from: http://ufdc.ufl.edu/UFE0041220

EPFL

17. Buth, Sergii. Structure and Function of Essential Components of Contractile Injection Systems.

Degree: 2014, EPFL

URL: http://infoscience.epfl.ch/record/196246

Subjects/Keywords: type VI secretion system; T6SS; R-type pyocin; bacteriophage; T4; cell-puncturing device; contractile injection systems; CryoEM; X-ray crystallography

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Buth, S. (2014). Structure and Function of Essential Components of Contractile Injection Systems. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/196246

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Buth, Sergii. “Structure and Function of Essential Components of Contractile Injection Systems.” 2014. Thesis, EPFL. Accessed December 07, 2019. http://infoscience.epfl.ch/record/196246.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Buth, Sergii. “Structure and Function of Essential Components of Contractile Injection Systems.” 2014. Web. 07 Dec 2019.

Vancouver:

Buth S. Structure and Function of Essential Components of Contractile Injection Systems. [Internet] [Thesis]. EPFL; 2014. [cited 2019 Dec 07]. Available from: http://infoscience.epfl.ch/record/196246.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Buth S. Structure and Function of Essential Components of Contractile Injection Systems. [Thesis]. EPFL; 2014. Available from: http://infoscience.epfl.ch/record/196246

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Texas Medical Branch – Galveston

18. [No author]. Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response .

Degree: University of Texas Medical Branch – Galveston

URL: http://hdl.handle.net/2152.3/780

► Aeromonas hydrophila is a Gram-negative bacterium which produces a wide variety of virulence factors leading to both intestinal and extra-intestinal infections in humans. A large… (more)

▼ Aeromonas hydrophila is a Gram-negative bacterium which produces a wide variety of virulence factors leading to both intestinal and extra-intestinal infections in humans. A large number of water and clinical Aeromonas isolates were molecularly finger-printed and our data provided the evidence of successful colonization and infection of humans with particular strains of certain Aeromonas species after consumption of water. Further, we delineated the role of N-acyl homoserine lactones (AHLs; autoinducer-1 [AI-1])-mediated quorum sensing (QS) in the virulence of a diarrheal isolate SSU of A. hydrophila by generating a ΔahyRI mutant. Our data suggested that AI-1-mediated QS modulated the in vitro virulence of A. hydrophila by regulating type 6 secretion effectors, metallo-protease production, and biofilm formation. In a septicemic mouse model, the ΔahyRI mutant was also attenuated as compared to the parental strain of A. hydrophila. In addition, we demonstrated that AHLs possess immunomodulatory and protective roles and AHL pretreatment modulates innate immune response in mice and enhances their survivability during A. hydrophila infection. Further, AHL treated animals exhibited a significantly reduced bacterial load in the blood and other mouse organs, as well as various levels of cytokines/chemokines as compared to control animals. Importantly, AHL pretreatment significantly elevated neutrophil numbers in the blood, suggesting that neutrophils quickly cleared bacteria either by phagocytosis or possibly other mechanism(s) during infection. These findings coincided with the fact that neutropenic animals were more susceptible to A. hydrophila infection than normal mice. We showed that animals challenged with A. hydrophila die because of kidney and liver damage, hypoglycemia, and thrombocytopenia, and, importantly, pretreatment of animals with AHLs prevented clinical sequelae, resulting in increased survivability of mice. Finally, we identified and characterized a new two-component based QseBC/AI-3 QS system in A. hydrophila SSU by generating a ΔqseB mutant. We noted that deletion of the qseB gene attenuated bacterial virulence in a septicemic mouse model of infection, had diminished swimming and swarming motility, and the mutant bacteria formed denser biofilms when compared to the parental strain of A. hydrophila. The decrease in the virulence of A. hydrophila ∆qseB mutant correlated with reduced production of protease and the cytotoxic enterotoxin, which has associated hemolytic activity. Advisors/Committee Members: Chopra, Ashok K (advisor), Peterson, Johnny W (committeeMember), Suzuki, Fujio (committeeMember), Motin, Vladimir (committeeMember), Pancholi, Vijay (committeeMember).

Subjects/Keywords: Aeromonas hydrophila; quorum sensing; AHLs; QseBC; virulence factors; biofilm formation; motility; T6SS; protease production; septicemic mouse model of infection

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

author], [. (n.d.). Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response . (Thesis). University of Texas Medical Branch – Galveston. Retrieved from http://hdl.handle.net/2152.3/780

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

author], [No. “Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response .” Thesis, University of Texas Medical Branch – Galveston. Accessed December 07, 2019. http://hdl.handle.net/2152.3/780.

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

author], [No. “Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response .” Web. 07 Dec 2019.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

author] [. Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response . [Internet] [Thesis]. University of Texas Medical Branch – Galveston; [cited 2019 Dec 07]. Available from: http://hdl.handle.net/2152.3/780.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

Council of Science Editors:

author] [. Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response . [Thesis]. University of Texas Medical Branch – Galveston; Available from: http://hdl.handle.net/2152.3/780

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations