scholarly journals Generation of Xylose-inducible promoter tools for Pseudomonas species and their use in implicating a role for the Type II secretion system protein XcpQ in inhibition of corneal epithelial wound closure

2020 ◽  
Author(s):  
Jake D. Callaghan ◽  
Nicholas A. Stella ◽  
Kara M. Lehner ◽  
Benjamin R. Treat ◽  
Kimberly M. Brothers ◽  
...  
Keyword(s):  
Gene Expression ◽  
Wound Closure ◽  
Inducible Promoter ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Corneal Epithelial ◽  
E Coli ◽  
Type Ii Secretion System ◽  
Promoter System

ABSTRACTTunable control of gene expression is an invaluable tool for biological experiments. In this study, we describe a new xylose-inducible promoter system and evaluate it in both Pseudomonas aeruginosa and P. fluorescens. The Pxut promoter derived from the P. flurorescens xut operon was incorporated into a broad host-range pBBR1-based plasmid and compared to the Escherichia coli-derived PBAD promoter using gfp as a reporter. GFP-fluorescence from the Pxut promoter was inducible in both Pseudomonas species, but not in E. coli, which may facilitate cloning of toxic genes using E. coli to generate plasmids. The Pxut promoter was expressed at a lower inducer concentration than PBAD in P. fluorescens and higher gfp levels were achieved using Pxut. Flow cytometry analysis indicated that Pxut was more leaky than PBAD in the tested Pseudomonas species, but was expressed in a higher proportion of cells when induced. D-xylose did not support growth of P. aeruginosa or P. fluorescens as a sole carbon source and is less expensive than many other commonly used inducers which could facilitate large scale applications. The efficacy of this system aided in demonstrating a role for the P. aeruginosa type II secretion system gene from xcpQ in bacterial inhibition of corneal epithelial cell wound closure. This study introduces a new inducible promoter system for gene expression for use in Pseudomonas species.ImportancePseudomonas species are enormously important in human infections, biotechnology, and as a model system for interrogating basic science questions. In this study we have developed a xylose-inducible promoter system and evaluated it in P. aeruginosa and P. fluorescens and found it to be suitable for the strong induction of gene expression. Furthermore, we have demonstrated its efficacy in controlled gene expression to show that a type 2 secretion system protein from P. aeruginosa, XcpQ, is important for host-pathogen interactions in a corneal wound closure model.

scholarly journals Xylose-Inducible Promoter Tools for Pseudomonas Species and Their Use in Implicating a Role for the Type II Secretion System Protein XcpQ in the Inhibition of Corneal Epithelial Wound Closure

2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Jake D. Callaghan ◽  
Nicholas A. Stella ◽  
Kara M. Lehner ◽  
Benjamin R. Treat ◽  
Kimberly M. Brothers ◽  
...  
Keyword(s):  
Gene Expression ◽  
Wound Closure ◽  
Inducible Promoter ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Content Type ◽  
Corneal Epithelial ◽  
Type Ii Secretion System ◽  
Promoter System

ABSTRACT Tunable control of gene expression is an invaluable tool for biological experiments. In this study, we describe a new xylose-inducible promoter system and evaluate it in both Pseudomonas aeruginosa and Pseudomonas fluorescens. The Pxut promoter, derived from the P. fluorescens xut operon, was incorporated into a broad-host-range pBBR1-based plasmid and was compared to the Escherichia coli-derived PBAD promoter using gfp as a reporter. Green fluorescent protein (GFP) fluorescence from the Pxut promoter was inducible in both Pseudomonas species, but not in E. coli, which may facilitate the cloning of genes toxic to E. coli to generate plasmids. The Pxut promoter was activated at a lower inducer concentration than PBAD in P. fluorescens, and higher gfp levels were achieved using Pxut. Flow cytometry analysis indicated that Pxut was leakier than PBAD in the Pseudomonas species tested but was expressed in a higher proportion of cells when induced. d-Xylose as a sole carbon source did not support the growth of P. aeruginosa or P. fluorescens and is less expensive than many other commonly used inducers, which could facilitate large-scale applications. The efficacy of this system was demonstrated by its use to reveal a role for the P. aeruginosa type II secretion system gene xcpQ in bacterial inhibition of corneal epithelial cell wound closure. This study introduces a new inducible promoter system for gene expression for use in Pseudomonas species. IMPORTANCE Pseudomonas species are enormously important in human infections, in biotechnology, and as model systems for investigating basic science questions. In this study, we have developed a xylose-inducible promoter system, evaluated it in P. aeruginosa and P. fluorescens, and found it to be suitable for the strong induction of gene expression. Furthermore, we have demonstrated its efficacy in controlled gene expression to show that a type II secretion system protein from P. aeruginosa, XcpQ, is important for host-pathogen interactions in a corneal wound closure model.

scholarly journals Porcine Enterotoxigenic Escherichia coli Strains Differ in Their Capacity To Secrete Enterotoxins through Varying YghG Levels

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Haixiu Wang ◽  
Raquel Sanz Garcia ◽  
Eric Cox ◽  
Bert Devriendt
Keyword(s):  
Escherichia Coli ◽  
Secretion System ◽  
Farm Animals ◽  
Health Concern ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Content Type ◽  
E Coli ◽  
Type Ii Secretion System ◽  
Heat Labile

ABSTRACT Enterotoxigenic Escherichia coli (ETEC) strains are important pathogens for humans and farm animals such as pigs. Porcine ETEC strains induce diarrhea through the production of heat-labile enterotoxin (LT) and/or heat-stable enterotoxins (pSTa/STb). Although LT secretion levels differ between porcine ETEC strains, and this has been linked to virulence, it is unclear whether ST secretion levels also differ between porcine ETEC strains. In addition, the molecular mechanism underlying different LT secretion levels has not been elucidated. In this work, multiple porcine ETEC strains were assessed for their capacity to produce and secrete the enterotoxins LT, pSTa, and STb. The strains differed greatly in their capacity to secrete LT, pSTa, and STb. Remarkably, in some strains, periplasmic production did not correlate with their ability to secrete LT, resulting in high periplasmic production and low LT secretion levels. Furthermore, the results indicated that the type II secretion system (T2SS) protein YghG plays a regulatory role in controlling LT secretion levels. These findings highlight YghG as an important mediator of the secretion of the heat-labile enterotoxin LT by porcine ETEC strains and provide better insights into ETEC enterotoxin secretion. IMPORTANCE Enterotoxigenic E. coli strains are a major health concern. Enterotoxins secreted by enterotoxigenic E. coli are crucial for diarrhea induction. Enterotoxin secretion levels differ between strains; however, it is currently unclear what drives these differences. The discrepancy in the production and secretion capacities of enterotoxins in ETEC is important to clarify their function involved in diarrhea induction. Our results further deepen our understanding of how type II secretion system (T2SS) components of ETEC control enterotoxin secretion levels and may lay the foundation for a better understanding of ETEC molecular pathogenesis.

scholarly journals Alterations in Peptidoglycan Cross-Linking Suppress the Secretin Assembly Defect Caused by Mutation of GspA in the Type II Secretion System

2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Elizabeth M. Vanderlinde ◽  
Timothy G. Strozen ◽  
Sara B. Hernández ◽  
Felipe Cava ◽  
S. Peter Howard
Keyword(s):  
Outer Membrane ◽  
Secretion System ◽  
Cross Linking ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Assembly Model ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Type Ii Secretion System

ABSTRACT In Gram-negative bacteria, the peptidoglycan (PG) cell wall is a significant structural barrier for outer membrane protein assembly. In Aeromonas hydrophila, outer membrane multimerization of the type II secretion system (T2SS) secretin ExeD requires the function of the inner membrane assembly factor complex ExeAB. The putative mechanism of the complex involves the reorganization of PG and localization of ExeD, whereby ExeA functions by interacting with PG to form a site for secretin assembly and ExeB forms an interaction with ExeD. This mechanism led us to hypothesize that increasing the pore size of PG would circumvent the requirement for ExeA in the assembly of the ExeD secretin. Growth of A. hydrophila in 270 mM Gly reduced PG cross-links by approximately 30% and led to the suppression of secretin assembly defects in exeA strains and in those expressing ExeA mutants by enabling localization of the secretin in the outer membrane. We also established a heterologous ExeD assembly system in Escherichia coli and showed that ExeAB and ExeC are the only A. hydrophila proteins required for the assembly of the ExeD secretin in E. coli and that ExeAB-independent assembly of ExeD can occur upon overexpression of the d,d-carboxypeptidase PBP 5. These results support an assembly model in which, upon binding to PG, ExeA induces multimerization and pore formation in the sacculus, which enables ExeD monomers to interact with ExeB and assemble into a secretin that both is inserted in the outer membrane and crosses the PG layer to interact with the inner membrane platform of the T2SS. IMPORTANCE The PG layer imposes a strict structural impediment for the assembly of macromolecular structures that span the cell envelope and serve as virulence factors in Gram-negative species. This work revealed that by decreasing PG cross-linking by growth in Gly, the absolute requirement for the PG-binding activity of ExeA in the assembly of the ExeD secretin was alleviated in A. hydrophila. In a heterologous assembly model in E. coli, expression of the carboxypeptidase PBP 5 could relieve the requirement for ExeAB in the assembly of the ExeD secretin. These results provide some mechanistic details of the ExeAB assembly complex function, in which the PG-binding and oligomerization functions of ExeAB are used to create a pore in the PG that is required for secretin assembly.

scholarly journals Solution Structure of Homology Region (HR) Domain of Type II Secretion System

2012 ◽  
Vol 287 (12) ◽  
pp. 9072-9080 ◽  
Author(s):  
Shuang Gu ◽  
Geoff Kelly ◽  
Xiaohui Wang ◽  
Tom Frenkiel ◽  
Vladimir E. Shevchik ◽  
...  
Keyword(s):  
Solution Structure ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Homology Region ◽  
Type Ii Secretion System

scholarly journals Structural and Functional Studies on the Interaction of GspC and GspD in the Type II Secretion System

2011 ◽  
Vol 7 (9) ◽  
pp. e1002228 ◽  
Author(s):  
Konstantin V. Korotkov ◽  
Tanya L. Johnson ◽  
Michael G. Jobling ◽  
Jonathan Pruneda ◽  
Els Pardon ◽  
...  
Keyword(s):  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Functional Studies ◽  
Type Ii Secretion System

scholarly journals Direct Involvement of Type II Secretion System in Extracellular Translocation of Shewanella oneidensis Outer Membrane Cytochromes MtrC and OmcA

2008 ◽  
Vol 190 (15) ◽  
pp. 5512-5516 ◽  
Author(s):  
Liang Shi ◽  
Shuang Deng ◽  
Matthew J. Marshall ◽  
Zheming Wang ◽  
David W. Kennedy ◽  
...  
Keyword(s):  
Cell Surface ◽  
Shewanella Oneidensis ◽  
Secretion System ◽  
Proteinase K ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Direct Involvement ◽  
Type Ii Secretion System ◽  
Extracellular Release ◽  
Proteinase K Treatment

ABSTRACT MtrC and OmcA are cell surface-exposed lipoproteins important for reducing solid metal oxides. Deletions of type II secretion system (T2SS) genes reduced their extracellular release and their accessibility to the proteinase K treatment, demonstrating the direct involvement of T2SS in translocation of MtrC and OmcA to the bacterial cell surface.

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