scholarly journals Pathogenicity Island in Salmonella

2021 ◽  
Author(s):  
Sarika Kombade ◽  
Navneet Kaur
Keyword(s):  
Regulatory Network ◽  
Secretion System ◽  
Effector Proteins ◽  
Pathogenicity Islands ◽  
Drug Investigation ◽  
Prevention Of Infection ◽  
Important Virulence Factor ◽  
Salmonella Pathogenicity Islands ◽  
Insight Into ◽  
Complex Regulatory Network

Considering a complex set of interplay with its host, Salmonella needs numerous genes for its full virulence. These genes responsible for invasion, survival, and extra intestinal spread are located on pathogenicity islands known as Salmonella pathogenicity islands (SPIs) that are thought to be acquired by horizontal gene transfer. A total of 17 SPIs (1–17) are recognized so far. The type III secretion system (T3SS) encoded by SPI-1 is considered as the most important virulence factor for Salmonella that delivers effector proteins necessary for invasion and production of enteritis. Among various SPIs, the role in virulence is well proven for SPI1 and SPI2 and further insight into the complex regulatory network of SPIs can contribute to drug investigation and prevention of infection.

scholarly journals Regulation of the Locus of Enterocyte Effacement in Attaching and Effacing Pathogens

2017 ◽  
Vol 200 (2) ◽  
Author(s):  
R. Christopher D. Furniss ◽  
Abigail Clements
Keyword(s):  
Secretion System ◽  
Effector Proteins ◽  
The Core ◽  
Genetic Feature ◽  
Gut Epithelium ◽  
Type Three Secretion System ◽  
Gut Mucosa ◽  
Enterocyte Effacement ◽  
Type Three Secretion ◽  
Complex Regulatory Network

ABSTRACTAttaching and effacing (AE) pathogens colonize the gut mucosa using a type three secretion system (T3SS) and a suite of effector proteins. The locus of enterocyte effacement (LEE) is the defining genetic feature of the AE pathogens, encoding the T3SS and the core effector proteins necessary for pathogenesis. Extensive research has revealed a complex regulatory network that senses and responds to a myriad of host- and microbiota-derived signals in the infected gut to control transcription of the LEE. These signals include microbiota-liberated sugars and metabolites in the gut lumen, molecular oxygen at the gut epithelium, and host hormones. Recent research has revealed that AE pathogens also recognize physical signals, such as attachment to the epithelium, and that the act of effector translocation remodels gene expression in infecting bacteria. In this review, we summarize our knowledge to date and present an integrated view of how chemical, geographical, and physical cues regulate the virulence program of AE pathogens during infection.

scholarly journals Exopolysaccharide protectsVibrio choleraefrom exogenous attacks by the type 6 secretion system

2018 ◽  
Vol 115 (31) ◽  
pp. 7997-8002 ◽  
Author(s):  
Jonida Toska ◽  
Brian T. Ho ◽  
John J. Mekalanos
Keyword(s):  
Biofilm Formation ◽  
Potential Role ◽  
Secretion System ◽  
Effector Proteins ◽  
Solid Surfaces ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Macromolecular Protein ◽  
Insight Into

The type 6 secretion system (T6SS) is a nanomachine used by many Gram-negative bacteria, includingVibrio cholerae, to deliver toxic effector proteins into adjacent eukaryotic and bacterial cells. Because the activity of the T6SS is dependent on direct contact between cells, its activity is limited to bacteria growing on solid surfaces or in biofilms.V. choleraecan produce an exopolysaccharide (EPS) matrix that plays a role in adhesion and biofilm formation. In this work, we investigated the effect of EPS production on T6SS activity between cells. We found that EPS produced byV. choleraecells functions as a unidirectional protective armor that blocks exogenous T6SS attacks without interfering with its own T6SS functionality. This EPS armor is effective against both same-species and heterologous attackers. Mutations modulating the level of EPS biosynthesis gene expression result in corresponding modulation inV. choleraeresistance to exogenous T6SS attack. These results provide insight into the potential role of extracellular biopolymers, including polysaccharides, capsules, and S-layers in protecting bacterial cells from attacks involving cell-associated macromolecular protein machines that cannot readily diffuse through these mechanical defenses.

scholarly journals Comparative Analysis of Locus of Enterocyte Effacement Pathogenicity Islands of Atypical Enteropathogenic Escherichia coli

2004 ◽  
Vol 72 (11) ◽  
pp. 6722-6728 ◽  
Author(s):  
Julia F. Gärtner ◽  
M. Alexander Schmidt
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Functional Expression ◽  
Secretion System ◽  
Effector Proteins ◽  
Eukaryotic Cells ◽  
Pathogenicity Islands ◽  
E Coli ◽  
Enterocyte Effacement ◽  
Pedestal Formation

ABSTRACT The pathogenicity of enteropathogenic Escherichia coli (EPEC) is linked to the locus of enterocyte effacement, or LEE, encoding a type III secretion system (T3SS) that directly transfers bacterial effector proteins into eukaryotic cells. Atypical diffusely adhering EPEC (DA-EPEC) strains that harbor homologues of the LEE but lack the EPEC adherence factor plasmid have been increasingly associated with outbreaks of diarrhea. In this study, we have completely sequenced and functionally characterized LEE pathogenicity islands derived from the clinical DA-EPEC isolates 3431 (O8:H−) and 0181 (O119:H9:K61). LEE3431 and LEE0181 exhibit genetic organization analogous to that of the prototype LEEE2348/69. Genes constituting the T3SS apparatus are highly conserved. However, LEE-encoded effector proteins exhibit major differences. Transfer and functional expression of LEE0181 in an E. coli XL1 blue MR background demonstrated that LEE0181 contains all the information for signal transduction and pedestal formation.

scholarly journals Salmonella enterica Subsp. houtenae Associated with an Abscess in Young Roe Deer (Capreolus capreolus)

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 654
Author(s):  
Adriana Trotta ◽  
Laura Del Sambro ◽  
Michela Galgano ◽  
Stefano Ciccarelli ◽  
Erika Ottone ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Roe Deer ◽  
Capreolus Capreolus ◽  
Epidemiological Data ◽  
Resistance Pattern ◽  
Salmonella Spp ◽  
Antibiotic Resistant ◽  
Biochemical Identification ◽  
Salmonella Pathogenicity Islands ◽  
Insight Into

Background: S. enterica subsp. houtenae has been rarely documented, and very limited genomic information is available. This report describes a rare case of primary extraintestinal salmonellosis in a young roe deer, associated with Salmonella enterica subsp. houtenae. Methods: A traditional cultural-based analysis was carried out from the contents of a neck abscess; biochemical identification and PCR assay were performed to isolate and identify the pathogen. Through whole-genome sequencing (WGS), multilocus sequence typing (MLST), core genome MLST (cgMLST), and the Salmonella pathogenicity islands (SPIs) survey, resistome and virulome genes were investigated to gain insight into the virulence and antimicrobial resistance of S. houtenae. Results: Biochemical identification and PCR confirmed the presence of Salmonella spp. in the swelling. The WGS analysis identified Salmonella enterica subspecies houtenae serovar 43:z4,z23:- and ST 958. The virulence study predicted a multidrug resistance pattern with resistance shown against aminoglycosides, tetracycline, beta-lactamase, fluoroquinolones, fosfomycin, nitroimidazole, aminocoumarin, and peptide. Fifty-three antibiotic-resistant genes were identified. No plasmids were detected. Conclusion: This study demonstrates the importance of continuous surveillance of pathogenic salmonellae. Biomolecular analyses combined with epidemiological data can provide important information about poorly described Salmonella strains and can help to improve animal welfare.

scholarly journals The HrpG/HrpX Regulon of Xanthomonads—An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria

2021 ◽  
Vol 9 (1) ◽  
pp. 187
Author(s):  
Doron Teper ◽  
Sheo Shankar Pandey ◽  
Nian Wang
Keyword(s):  
Regulatory Network ◽  
Regulatory Networks ◽  
Focal Point ◽  
Genetic Regulation ◽  
Transcriptional Regulators ◽  
Secretion System ◽  
In Planta ◽  
Type 3 Secretion System ◽  
Type 3 ◽  
Made In

Bacteria of the genus Xanthomonas cause a wide variety of economically important diseases in most crops. The virulence of the majority of Xanthomonas spp. is dependent on secretion and translocation of effectors by the type 3 secretion system (T3SS) that is controlled by two master transcriptional regulators HrpG and HrpX. Since their discovery in the 1990s, the two regulators were the focal point of many studies aiming to decipher the regulatory network that controls pathogenicity in Xanthomonas bacteria. HrpG controls the expression of HrpX, which subsequently controls the expression of T3SS apparatus genes and effectors. The HrpG/HrpX regulon is activated in planta and subjected to tight metabolic and genetic regulation. In this review, we cover the advances made in understanding the regulatory networks that control and are controlled by the HrpG/HrpX regulon and their conservation between different Xanthomonas spp.

scholarly journals Pseudomonas syringae Strains Naturally Lacking the Classical P. syringae hrp/hrc Locus Are Common Leaf Colonizers Equipped with an Atypical Type III Secretion System

2010 ◽  
Vol 23 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Christopher R. Clarke ◽  
Rongman Cai ◽  
David J. Studholme ◽  
David S. Guttman ◽  
Boris A. Vinatzer
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Plant Cells ◽  
Type Iii Secretion System ◽  
Ice Nucleation ◽  
Secretion System ◽  
Effector Proteins ◽  
Population Densities ◽  
Type Iii ◽  
Effector Genes

Pseudomonas syringae is best known as a plant pathogen that causes disease by translocating immune-suppressing effector proteins into plant cells through a type III secretion system (T3SS). However, P. syringae strains belonging to a newly described phylogenetic subgroup (group 2c) are missing the canonical P. syringae hrp/hrc cluster coding for a T3SS, flanking effector loci, and any close orthologue of known P. syringae effectors. Nonetheless, P. syringae group 2c strains are common leaf colonizers and grow on some tested plant species to population densities higher than those obtained by other P. syringae strains on nonhost species. Moreover, group 2c strains have genes necessary for the production of phytotoxins, have an ice nucleation gene, and, most interestingly, contain a novel hrp/hrc cluster, which is only distantly related to the canonical P. syringae hrp/hrc cluster. This hrp/hrc cluster appears to encode a functional T3SS although the genes hrpK and hrpS, present in the classical P. syringae hrp/hrc cluster, are missing. The genome sequence of a representative group 2c strain also revealed distant orthologues of the P. syringae effector genes avrE1 and hopM1 and the P. aeruginosa effector genes exoU and exoY. A putative life cycle for group 2c P. syringae is discussed.

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