scholarly journals Systematic Deletion of Type III Secretion System Effectors in Enteropathogenic E. coli Unveils the Role of Non-LEE Effectors in A/E Lesion Formation

2020 ◽  
Author(s):  
Massiel Cepeda-Molero ◽  
Stephanie Schüller ◽  
Gad Frankel ◽  
Luis Ángel Fernández
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Lesion Formation ◽  
E Coli ◽  
Type Iii

Effect of plant systemic resistance and role of type III secretion system in colonization of basil and lettuce by Salmonella enterica

2015 ◽  
Author(s):  
Shulamit Manulis ◽  
Maria Brandl ◽  
Isaac Barash ◽  
Laura Chalupowicz ◽  
Michael McClelland ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Systemic Resistance ◽  
Type Iii

scholarly journals Use of the Galleria mellonella Caterpillar as a Model Host To Study the Role of the Type III Secretion System in Pseudomonas aeruginosa Pathogenesis

2003 ◽  
Vol 71 (5) ◽  
pp. 2404-2413 ◽  
Author(s):  
Sachiko Miyata ◽  
Monika Casey ◽  
Dara W. Frank ◽  
Frederick M. Ausubel ◽  
Eliana Drenkard
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Galleria Mellonella ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Triple Mutant ◽  
Type Iii ◽  
Wax Moth

ABSTRACT Nonvertebrate model hosts represent valuable tools for the study of host-pathogen interactions because they facilitate the identification of bacterial virulence factors and allow the discovery of novel components involved in host innate immune responses. In this report, we determined that the greater wax moth caterpillar Galleria mellonella is a convenient nonmammalian model host for study of the role of the type III secretion system (TTSS) in Pseudomonas aeruginosa pathogenesis. Based on the observation that a mutation in the TTSS pscD gene of P. aeruginosa strain PA14 resulted in a highly attenuated virulence phenotype in G. mellonella, we examined the roles of the four known effector proteins of P. aeruginosa (ExoS, ExoT, ExoU, and ExoY) in wax moth killing. We determined that in P. aeruginosa strain PA14, only ExoT and ExoU play a significant role in G. mellonella killing. Strain PA14 lacks the coding sequence for the ExoS effector protein and does not seem to express ExoY. Moreover, using ΔexoU ΔexoY, ΔexoT ΔexoY, and ΔexoT ΔexoU double mutants, we determined that individual translocation of either ExoT or ExoU is sufficient to obtain nearly wild-type levels of G. mellonella killing. On the other hand, data obtained with a ΔexoT ΔexoU ΔexoY triple mutant and a ΔpscD mutant suggested that additional, as-yet-unidentified P. aeruginosa components of type III secretion are involved in virulence in G. mellonella. A high level of correlation between the results obtained in the G. mellonella model and the results of cytopathology assays performed with a mammalian tissue culture system validated the use of G. mellonella for the study of the P. aeruginosa TTSS.

scholarly journals Escherichia coli type III secretion system 2 (ETT2) is widely distributed in avian pathogenic Escherichia coli isolates from Eastern China

2016 ◽  
Vol 144 (13) ◽  
pp. 2824-2830 ◽  
Author(s):  
S. WANG ◽  
X. LIU ◽  
X. XU ◽  
Y. ZHAO ◽  
D. YANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Bacterial Infections ◽  
Eastern China ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Secretion Systems ◽  
E Coli ◽  
Type Iii ◽  
System 2

SUMMARYPathogens utilize type III secretion systems to deliver effector proteins, which facilitate bacterial infections. The Escherichia coli type III secretion system 2 (ETT2) which plays a crucial role in bacterial virulence, is present in the majority of E. coli strains, although ETT2 has undergone widespread mutational attrition. We investigated the distribution and characteristics of ETT2 in avian pathogenic E. coli (APEC) isolates and identified five different ETT2 isoforms, including intact ETT2, in 57·6% (141/245) of the isolates. The ETT2 locus was present in the predominant APEC serotypes O78, O2 and O1. All of the ETT2 loci in the serotype O78 isolates were degenerate, whereas an intact ETT2 locus was mostly present in O1 and O2 serotype strains, which belong to phylogenetic groups B2 and D, respectively. Interestingly, a putative second type III secretion-associated locus (eip locus) was present only in the isolates with an intact ETT2. Moreover, ETT2 was more widely distributed in APEC isolates and exhibited more isoforms compared to ETT2 in human extraintestinal pathogenic E. coli, suggesting that APEC might be a potential risk to human health. However, there was no distinct correlation between ETT2 and other virulence factors in APEC.

scholarly journals A Degenerate Type III Secretion System from Septicemic Escherichia coli Contributes to Pathogenesis

2005 ◽  
Vol 187 (23) ◽  
pp. 8164-8171 ◽  
Author(s):  
Diana Ideses ◽  
Uri Gophna ◽  
Yossi Paitan ◽  
Roy R. Chaudhuri ◽  
Mark J. Pallen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Gene Clusters ◽  
Secretion System ◽  
Effector Proteins ◽  
E Coli ◽  
Type Iii

ABSTRACT The type III secretion system (T3SS) is an important virulence factor used by several gram-negative bacteria to deliver effector proteins which subvert host cellular processes. Enterohemorrhagic Escherichia coli O157 has a well-defined T3SS involved in attachment and effacement (ETT1) and critical for virulence. A gene cluster potentially encoding an additional T3SS (ETT2), which resembles the SPI-1 system in Salmonella enterica, was found in its genome sequence. The ETT2 gene cluster has since been found in many E. coli strains, but its in vivo role is not known. Many of the ETT2 gene clusters carry mutations and deletions, raising the possibility that they are not functional. Here we show the existence in septicemic E. coli strains of an ETT2 gene cluster, ETT2sepsis, which, although degenerate, contributes to pathogenesis. ETT2sepsis has several premature stop codons and a large (5 kb) deletion, which is conserved in 11 E. coli strains from cases of septicemia and newborn meningitis. A null mutant constructed to remove genes coding for the putative inner membrane ring of the secretion complex exhibited significantly reduced virulence. These results are the first demonstration of the importance of ETT2 for pathogenesis.

scholarly journals Expression of the Type III Secretion System Genes in Epiphytic Erwinia amylovora Cells on Apple Stigmas Benefits Endophytic Infection at the Hypanthium

2021 ◽  
Author(s):  
Zhouqi Cui ◽  
Regan B. Huntley ◽  
Neil P Schultes ◽  
Kaleem U. Kakar ◽  
Ching-Hong Yang ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Erwinia Amylovora ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Subsequent Infection ◽  
Type Iii ◽  
Entry Points ◽  
Important Virulence Factor ◽  
Open Access Article

Erwinia amylovora causes fire blight on rosaceous plants. One of the major entry points of E. amylovora into hosts is flowers, where E. amylovora proliferates epiphytically on stigmatic and hypanthium surfaces and, subsequently, causes endophytic infection at the hypanthium. The type III secretion system (T3SS) is an important virulence factor in E. amylovora. Although the role of T3SS during endophytic infection is well characterized, its expression during epiphytic colonization and role in the subsequent infection is less understood. Here, we investigated T3SS gene expression in epiphytic E. amylovora on stigma and hypanthium of apple flowers under different relative humidities (RH). On stigma surfaces, T3SS was expressed in a high percentage of E. amylovora cells, and its expression promoted epiphytic growth. On hypanthium surfaces, however, T3SS was expressed in fewer E. amylovora cells than on the stigma, and displayed no correlation with epiphytic growth, even though T3SS expression is essential for infection. E. amylovora cells grown on stigmatic surfaces and then flushed down to the hypanthium displayed a higher level of T3SS expression than cells grown on the hypanthium surface alone. Furthermore, E. amylovora cells precultured on stigma had a higher potential to infect flowers than E. amylovora cells precultured in a T3SS-repressive medium. This suggests that T3SS induction during the stigmatic epiphytic colonization may be beneficial for subsequent infection. Finally, epiphytic expression of T3SS was influenced by RH. Higher percentage of stigmatic E. amylovora cells expressed T3SS under high RH than under low RH. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals Role of SpaO in the assembly of the sorting platform of a Salmonella type III secretion system

2019 ◽  
Vol 15 (1) ◽  
pp. e1007565 ◽  
Author(s):  
Maria Lara-Tejero ◽  
Zhuan Qin ◽  
Bo Hu ◽  
Carmen Butan ◽  
Jun Liu ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii

scholarly journals Enterococcus faecalis Enhances Expression and Activity of the Enterohemorrhagic Escherichia coli Type III Secretion System

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Elizabeth A. Cameron ◽  
Vanessa Sperandio ◽  
Gary M. Dunny
Keyword(s):  
Enterococcus Faecalis ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Cell Contact ◽  
Content Type ◽  
E Coli ◽  
Type Iii ◽  
Expression And Activity

ABSTRACT The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses microbiota-derived molecules as cues to efficiently regulate virulence factor expression. Here, we investigate the interaction between EHEC and Enterococcus faecalis, a common human gut commensal, and show that E. faecalis affects both expression and activity of the EHEC type III secretion system (T3SS) via two distinct mechanisms. First, in the presence of E. faecalis there is increased transcription of genes encoding the EHEC T3SS. This leads to increased effector translocation and ultimately greater numbers of pedestals formed on host cells. The same effect was observed with several strains of enterococci, suggesting that it is a general characteristic of this group. In a mechanism separate from E. faecalis-induced transcription of the T3SS, we report that an E. faecalis-secreted protease, GelE, cleaves a critical structural component of the EHEC T3SS, EspB. Our data suggest that this cleavage actually increases effector translocation by the T3SS, supporting a model where EspB proteolysis promotes maximum T3SS activity. Finally, we report that treatment of EHEC with E. faecalis-conditioned cell-free medium is insufficient to induce increased T3SS expression, suggesting that this effect relies on cell contact between E. faecalis and EHEC. This work demonstrates a complex interaction between a human commensal and pathogen that impacts both expression and function of a critical virulence factor. IMPORTANCE This work reveals a complex and multifaceted interaction between a human gut commensal, Enterococcus faecalis, and a pathogen, enterohemorrhagic E. coli. We demonstrate that E. faecalis enhances expression of the enterohemorrhagic E. coli type III secretion system and that this effect likely depends on cell contact between the commensal and the pathogen. Additionally, the GelE protease secreted by E. faecalis cleaves a critical structural component of the EHEC type III secretion system. In agreement with previous studies, we find that this cleavage actually increases effector protein delivery into host cells by the secretion system. This work demonstrates that commensal bacteria can significantly shape expression and activity of pathogen virulence factors, which may ultimately shape the progression of disease.

Sign in / Sign up

Export Citation Format

Share Document