relA Enhances the Adherence of Enteropathogenic Escherichia coli

Spira, Beny; Ferreira, Gerson Moura; Almeida, Luiz Gustavo de

doi:10.1371/journal.pone.0091703

Cited by 13 publications

(17 citation statements)

References 52 publications

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“…The interaction network diagram of Vvrr1 with its potential target genes shows some of the target genes with their virulence function. For example, relA has been proved to enhance the adhesion of E. coli to host cells [58]. katG can increase the survival and escape rates of Aeromonas hydrophila in fish macrophages [59].…”

Section: Discussionmentioning

confidence: 99%

Mechanisms underlying the virulence regulation of new Vibrio alginolyticus ncRNA Vvrr1 with a comparative proteomic analysis

Zuo

Zhao

et al. 2019

Emerging Microbes & Infections

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The incidence of Vibrio alginolyticus infections has increased in recent years due to the influence of climate change and rising sea temperature. Vibrio virulence regulatory RNA 1 (Vvrr1) is a newly found noncoding RNA (ncRNA) predicted to be closely related to the adhesion ability of V. alginolyticus based on the previous RNA-seq. In this study, the target genes of Vvrr1 were fully screened and verified by constructing Vvrr1-overexpressing strains and using the proteome sequencing technology. Pyruvate kinase I (pykF) gene was predicted to be a chief target gene of Vvrr1 involved in virulence regulation. The adhesion ability, biofilm formation and virulence were significantly reduced in the Vvrr1-overexpressing and the pykFsilenced strain compared with the wild strains. Similar to the overexpression of Vvrr1, the silencing of pykF also reduced the expression level of virulence genes, such as ndk, eno, sdhB, glpF, and cysH. Meanwhile, by constructing the "pykF-GFP" fusion expression plasmid and using the GFP reporter gene analysis in Escherichia coli, the fluorescence intensity of the strain containing Vvrr1 whole ncRNA sequence vector was found to be significantly weakened. These indicated that Vvrr1 participated in the virulence regulation mechanism of V. alginolyticus by interacting with the virulence gene pykF.

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Section: Discussionmentioning

confidence: 99%

Mechanisms underlying the virulence regulation of new Vibrio alginolyticus ncRNA Vvrr1 with a comparative proteomic analysis

Zuo

Zhao

et al. 2019

Emerging Microbes & Infections

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“…ppGpp is positively associated with bacterial virulence in several species [8]. In E. coli pathotypes, such as EHEC, UPEC and EPEC ppGpp modulates the expression of virulence factors, such as the synthesis of adhesins and fimbriae important for bacterial attachment to the host cell [12–14]. However, it has been shown that ppGpp inhibits the lytic development and DNA replication of Stx bacteriophages, which suggests a negative role for ppGpp in the expression of virulence in bacteria that carry toxin-encoding phages such as STEC [15–17].…”

Section: Introductionmentioning

confidence: 99%

ppGpp and cytotoxicity diversity in Shiga toxin-producingEscherichia coli(STEC) isolates

et al. 2017

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Shiga toxin-producing Escherichia coli (STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across the E. coli species. In the present study, 50 STEC isolates from healthy sheep were evaluated regarding their ppGpp content, cytotoxicity and other relevant genetic and phenotypic characteristics. We found that the level of ppGpp and cytotoxicity varied considerably among the examined strains. Isolates that harboured the stx2 gene were the least cytotoxic and presented the highest levels of ppGpp. All stx2 isolates belonged to phylogroup A, while strains that carried stx1 or both stx1 and stx2 genes pertained to phylogroup B1. All but two stx2 isolates belonged to the stx2b subtype. Strains that belonged to phylogroup B1 displayed on average low levels of ppGpp and high cytotoxicity. Overall, there was a negative correlation between cytotoxicity and ppGpp.

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“…Initial studies suggested that the bundle-forming pilus (Bfp) participates in the initial intestinal interaction, but later experiments demonstrated that Bfp stabilizes microcolony formation (24). Recent studies suggested that the E. coli common pilus (ECP) and the product of the relA gene contribute to the interaction of EPEC with host epithelial cells (25,26); however, additional experiments are required to confirm the roles of these adhesins in vivo. Here, we mainly discuss the roles of H-NS-regulated products and Lpf in adhesion and colonization of the intestinal tract.…”

Section: Discussionmentioning

confidence: 99%

Finding Regulators Associated with the Expression of the Long Polar Fimbriae in Enteropathogenic Escherichia coli

Ross

Cieza

et al. 2015

J Bacteriol

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Enteropathogenic Escherichia coli (EPEC) is a human pathogen that requires initial adhesion to the intestine in order to cause disease. Multiple adhesion factors have been identified in E. coli strains, among them the long polar fimbriae (Lpf), a colonization factor associated with intestinal adhesion. The conditions of Lpf expression are well understood in enterohemorrhagic E. coli (EHEC); however, the expression of EPEC lpf has been found to be repressed under any in vitro condition tested. Therefore, we decided to identify those factors silencing expression of EPEC lpf. Because histone-like nucleoid structuring protein (H-NS) is a known repressor of EHEC lpf, we tested it and found that H-NS is a repressor of EPEC lpf. We also found that the adhesion of the EPEC ⌬hns strain was significantly enhanced compared to the wild-type strain. Because lpf expression was modestly increased in the hns mutant, transposon mutagenesis was performed to find a strain displaying higher lpf expression than EPEC ⌬hns. One Tn5 insertion was identified within the yhjX gene, and further in vitro characterization revealed increased lpf expression and adhesion to Caco-2 cells compared with EPEC ⌬hns. However, in a murine model of intestinal infection, the EPEC ⌬hns and EPEC ⌬hns Tn5 mutants had only a slight change in colonization pattern compared to the wild-type strain. Our data showed that EPEC Lpf is transcribed, but its role in EPEC intestinal colonization requires further analysis. IMPORTANCEData are presented demonstrating that the long polar fimbriae (lpf) operon in enteropathogenic E. coli (EPEC) is highly regulated; however, derepression occurs by mutagenizing two proteins associated with its control. The study demonstrates that the EPEC lpf operon can be expressed and, therefore, participates in the EPEC adherence phenotype. E scherichia coli bacteria are normally found in the intestines of humans and animals. Most E. coli strains rarely cause disease, except in immunocompromised hosts or in individuals whose normal gastrointestinal barrier is broken (1, 2). However, there are several E. coli strains that carry specific virulence attributes that classify them in specific pathotypes that cause distinct disease in healthy hosts (1). Two of these E. coli pathotypes, enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC), belong to the group of attaching and effacing E. coli (AEEC) strains. AEEC strains are characterized by the presence of a type III secretion system (T3SS) that injects virulence factors into the host cell, mediating the formation of the characterized histopathological attaching and effacing (A/E) lesion (1, 2). EPEC is a leading cause of human infantile diarrhea worldwide (3, 4). EHEC also causes severe human disease, including bloody diarrhea and life-threatening hemolytic uremic syndrome (HUS). Currently, EPEC is estimated to be responsible for 5 to 10% of pediatric diarrhea in developing countries (3). The Global Enteric Multicenter Study (GEMS) showed that some EPEC strains are assoc...

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relA Enhances the Adherence of Enteropathogenic Escherichia coli

Cited by 13 publications

References 52 publications

Mechanisms underlying the virulence regulation of new Vibrio alginolyticus ncRNA Vvrr1 with a comparative proteomic analysis

Mechanisms underlying the virulence regulation of new Vibrio alginolyticus ncRNA Vvrr1 with a comparative proteomic analysis

ppGpp and cytotoxicity diversity in Shiga toxin-producingEscherichia coli(STEC) isolates

Finding Regulators Associated with the Expression of the Long Polar Fimbriae in Enteropathogenic Escherichia coli

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