scholarly journals Pas, a Novel Protein Required for Protein Secretion and Attaching and Effacing Activities of Enterohemorrhagic Escherichia coli

1998 ◽  
Vol 180 (17) ◽  
pp. 4370-4379 ◽  
Author(s):  
Andreas U. Kresse ◽  
Kai Schulze ◽  
Christina Deibel ◽  
Frank Ebel ◽  
Manfred Rohde ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Secretion ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
Reading Frame ◽  
E Coli ◽  
Genes Encoding ◽  
Enterocyte Effacement ◽  
Putative Member

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) exhibits a pattern of localized adherence to host cells, with the formation of microcolonies, and induces a specific histopathological phenotype collectively known as the attaching and effacing lesion. The genes encoding the products responsible for this phenotype are located on a 35-kb pathogenicity island designated the locus of enterocyte effacement, which is also shared by enteropathogenic E. coli. We have identified an open reading frame (ORF) which is located upstream of the espA, espB, andespD genes on the complementary strand and which exhibits high homology to the genes spiB fromSalmonella, yscD from Yersinia, andpscD from Pseudomonas. Localization studies showed that the encoded product is present in the cytoplasmic and inner membrane fractions of EHEC. The construction and characterization of a recombinant clone containing an in-frame deletion of this ORF demonstrated that the encoded product is a putative member of a type III system required for protein secretion. Disruption of this ORF, designated pas (protein associated with secretion), abolished the secretion of Esp proteins. The mutant adhered only poorly and lost its capacities to trigger attaching and effacing activity and to invade HeLa cells. These results demonstrate that Pas is a virulence-associated factor that plays an essential role in EHEC pathogenesis.

scholarly journals Distribution, Functional Expression, and Genetic Organization of Cif, a Phage-Encoded Type III-Secreted Effector from Enteropathogenic and Enterohemorrhagic Escherichia coli

2007 ◽  
Vol 190 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Estelle Loukiadis ◽  
Rika Nobe ◽  
Sylvia Herold ◽  
Clara Tramuta ◽  
Yoshitoshi Ogura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Functional Expression ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
E Coli ◽  
Type Iii ◽  
Related Phenotype ◽  
Enterocyte Effacement ◽  
Lambdoid Prophage

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) inject effector proteins into host cells via a type III secretion system encoded by the locus of enterocyte effacement (LEE). One of these effectors is Cif, encoded outside the LEE by a lambdoid prophage. In this study, we demonstrated that the Cif-encoding prophage of EPEC strain E22 is inducible and produces infectious phage particles. We investigated the distribution and functional expression of Cif in 5,049 E. coli strains of human, animal, and environmental origins. A total of 115 E. coli isolates from diverse origins and geographic locations carried cif. The presence of cif was tightly associated with the LEE, since all the cif-positive isolates were positive for the LEE. These results suggested that the Cif-encoding prophages have been widely disseminated within the natural population of E. coli but positively selected within the population of LEE-positive strains. Nonetheless, 66% of cif-positive E. coli strains did not induce a typical Cif-related phenotype in eukaryotic cells due to frameshift mutations or insertion of an IS element in the cif gene. The passenger region of the prophages carrying cif was highly variable and showed various combinations of IS elements and genes coding for other effectors such as nleB, nleC, nleH, nleG, espJ, and nleA/espI (some of which were also truncated). This diversity and the presence of nonfunctional effectors should be taken into account to assess EPEC and EHEC pathogenicity and tropism.

scholarly journals The Locus of Enterocyte Effacement-Encoded Effector Proteins All Promote Enterohemorrhagic Escherichia coli Pathogenicity in Infant Rabbits

2005 ◽  
Vol 73 (3) ◽  
pp. 1466-1474 ◽  
Author(s):  
Jennifer M. Ritchie ◽  
Matthew K. Waldor
Keyword(s):  
Escherichia Coli ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Lesion Formation ◽  
Specific Effects ◽  
Genes Encoding ◽  
Organ Specific ◽  
Rabbit Intestine ◽  
Enterocyte Effacement

ABSTRACT The genes encoding the enterohemorrhagic Escherichia coli (EHEC) type III secretion system (TTSS) and five effector proteins secreted by the TTSS are located on the locus of enterocyte effacement (LEE) pathogenicity island. Deletion of tir, which encodes one of these effector proteins, results in a profound reduction (∼10,000-fold) in EHEC colonization of the infant rabbit intestine, but the in vivo phenotypes of other LEE genes are unknown. Here, we constructed in-frame deletions in escN, the putative ATPase component of the TTSS, and the genes encoding the four other LEE-encoded effector proteins, EspH, Map, EspF, and EspG, to investigate the contributions of the TTSS and the translocated effector proteins to EHEC pathogenicity in infant rabbits. We found that the TTSS is required for EHEC colonization and attaching and effacing (A/E) lesion formation in the rabbit intestine. Deletion of escN reduced EHEC recovery from the rabbit intestine by ∼10,000-fold. Although EspH, Map, EspF, and EspG were not required for A/E lesion formation in the rabbit intestine or in HeLa cells, these effector proteins promote EHEC colonization. Colonization by the espH and espF mutants was reduced throughout the intestine. In contrast, colonization by the map and espG mutants was reduced only in the small intestine, indicating that Map and EspG have organ-specific effects. EspF appears to down-regulate the host response to EHEC, since we observed increased accumulation of polymorphonuclear leukocytes in the colonic mucosa of rabbits infected with the EHEC espF mutant. Thus, all the known LEE-encoded effector proteins influence EHEC pathogenicity.

scholarly journals Cross-Reactive Protection against Enterohemorrhagic Escherichia coli Infection by Enteropathogenic E. coli in a Mouse Model

2011 ◽  
Vol 79 (6) ◽  
pp. 2224-2233 ◽  
Author(s):  
Carla Calderon Toledo ◽  
Ida Arvidsson ◽  
Diana Karpman
Keyword(s):  
Escherichia Coli ◽  
Weight Loss ◽  
Mouse Model ◽  
Enterohemorrhagic Escherichia Coli ◽  
Epec Strain ◽  
Content Type ◽  
E Coli ◽  
Renal Histology ◽  
Escherichia Coli Infection ◽  
Enterocyte Effacement

ABSTRACTEnteropathogenicEscherichia coli(EPEC) and enterohemorrhagicE. coli(EHEC) are related attaching and effacing (A/E) pathogens. The genes responsible for the A/E pathology are carried on a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE). Both pathogens share a high degree of homology in the LEE and additional O islands. EHEC prevalence is much lower in areas where EPEC is endemic. This may be due to the development of antibodies against common EPEC and EHEC antigens. This study investigated the hypothesis that EPEC infections may protect against EHEC infections. We used a mouse model to inoculate BALB/c mice intragastrically, first with EPEC and then with EHEC (E. coliO157:H7). Four control groups received either a nonpathogenicE. coli(NPEC) strain followed by EHEC (NPEC/EHEC), phosphate-buffered saline (PBS) followed by EHEC (PBS/EHEC), EPEC/PBS, or PBS/PBS. Mice were monitored for weight loss and symptoms. EPEC colonized the intestine after challenge, and mice developed serum antibodies to intimin andE. colisecreted protein B (encoded in the LEE). Prechallenge with an EPEC strain had a protective effect after EHEC infection, as only a few mice developed mild symptoms, from which they recovered. These mice had an increase in body weight similar to that in control animals, and tissue morphology exhibited mild intestinal changes and normal renal histology. All mice that were not prechallenged with the EPEC strain developed mild to severe symptoms after EHEC infection, with weight loss as well as intestinal and renal histopathological changes. These data suggest that EPEC may protect against EHEC infection in this mouse model.

scholarly journals Enterohemorrhagic Escherichia coli Virulence Regulation by Two Bacterial Adrenergic Kinases, QseC and QseE

2011 ◽  
Vol 80 (2) ◽  
pp. 688-703 ◽  
Author(s):  
Jacqueline Njoroge ◽  
Vanessa Sperandio
Keyword(s):  
Escherichia Coli ◽  
Response Regulator ◽  
Enterohemorrhagic Escherichia Coli ◽  
Dependent Manner ◽  
Content Type ◽  
E Coli ◽  
Virulence Regulation ◽  
Sensor Kinases ◽  
Virulence Factor Gene ◽  
Enterocyte Effacement

ABSTRACTThe human pathogen enterohemorrhagicEscherichia coli(EHEC) O157:H7 has two histidine sensor kinases, QseC and QseE, which respond to the mammalian adrenergic hormones epinephrine and norepinephrine by increasing their autophosphorylation. Although QseC and QseE are present in nonpathogenic strains ofE. coli, EHEC exploits these kinases for virulence regulation. To further investigate the full extent of epinephrine and its sensors' impact on EHEC virulence, we performed transcriptomic and phenotypic analyses of single and double deletions ofqseCandqseEgenes in the absence or presence of epinephrine. We showed that in EHEC, epinephrine sensing seems to occur primarily through QseC and QseE. We also observed that QseC and QseE regulate expression of the locus of enterocyte effacement (LEE) genes positively and negatively, respectively. LEE activation, which is required for the formation of the characteristic attaching and effacing (A/E) lesions by EHEC on epithelial cells, is epinephrine dependent. Regulation of the LEE and the non-LEE-contained virulence factor genenleAby QseE is indirect, through transcription inhibition of the RcsB response regulator. Finally, we show that coincubation of HeLa cells with epinephrine increases EHEC infectivity in a QseC- and QseE-dependent manner. These results genetically and phenotypically map the contributions of the two adrenergic sensors QseC and QseE to EHEC pathogenesis.

scholarly journals Rapid production and characterization of antimicrobial colicins using Escherichia coli-based cell-free protein synthesis

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Xing Jin ◽  
Weston Kightlinger ◽  
Yong-Chan Kwon ◽  
Seok Hoon Hong
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Host Cells ◽  
Persister Cells ◽  
Free Protein ◽  
E Coli ◽  
Dna And Rna ◽  
Rapid Production ◽  
Cell Free Protein Synthesis

Abstract Colicins are antimicrobial proteins produced by Escherichia coli, which, upon secretion from the host, kill non-host E. coli strains by forming pores in the inner membrane and degrading internal cellular components such as DNA and RNA. Due to their unique cell-killing activities, colicins are considered viable alternatives to conventional antibiotics. Recombinant production of colicins requires co-production of immunity proteins to protect host cells; otherwise, the colicins are lethal to the host. In this study, we used cell-free protein synthesis (CFPS) to produce active colicins without the need for protein purification and co-production of immunity proteins. Cell-free synthesized colicins were active in killing model E. coli cells with different modes of cytotoxicity. Pore-forming colicins E1 and nuclease colicin E2 killed actively growing cells in a nutrient-rich medium, but the cytotoxicity of colicin Ia was low compared to E1 and E2. Moreover, colicin E1 effectively killed cells in a nutrient-free solution, while the activity of E2 was decreased compared to nutrient-rich conditions. Both colicins E1 and E2 decreased the level of persister cells (metabolically dormant cell populations that are insensitive to antibiotics) by up to six orders of magnitude compared to that of the rifampin pretreated persister cells. This study finds that colicins can eradicate non-growing cells including persisters, and that CFPS is a promising platform for rapid production and characterization of toxic proteins.

scholarly journals Expression and Characterization of Streptococcal rgp Genes Required for Rhamnan Synthesis in Escherichia coli

2002 ◽  
Vol 70 (6) ◽  
pp. 2891-2898 ◽  
Author(s):  
Yukie Shibata ◽  
Yoshihisa Yamashita ◽  
Kazuhisa Ozaki ◽  
Yoshio Nakano ◽  
Toshihiko Koga
Keyword(s):  
Escherichia Coli ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polymerization Process ◽  
Streptococcus Sobrinus ◽  
E Coli ◽  
Genes Encoding ◽  
Group A ◽  
Specific Antigens

ABSTRACT Six genes (rgpA through rgpF) that were involved in assembling the rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans were previously identified (Y. Yamashita, Y. Tsukioka, K. Tomihisa, Y. Nakano, and T. Koga, J. Bacteriol. 180:5803-5807, 1998). The group-specific antigens of Lancefield group A, C, and E streptococci and the polysaccharide antigen of Streptococcus sobrinus have the same rhamnan backbone as the RGP of S. mutans. Escherichia coli harboring plasmid pRGP1 containing all six rgp genes did not synthesize complete RGP. However, E. coli carrying a plasmid with all of the rgp genes except for rgpE synthesized the rhamnan backbone of RGP without glucose side chains, suggesting that in addition to rgpE, another gene is required for glucose side-chain formation. Synthesis of the rhamnan backbone in E. coli required the initiation of transfer of N-acetylglucosamine to a lipid carrier and the expression of the rgpC and rgpD genes encoding the putative ABC transporter specific for RGP. The similarities in RGP synthesis between E. coli and S. mutans suggest common pathways for rhamnan synthesis. Therefore, we evaluated the rhamnosyl polymerization process in E. coli by high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the lipooligosaccharide (LOS). An E. coli transformant harboring rgpA produced the LOS modified by the addition of a single rhamnose residue. Furthermore, the rgpA, rgpB, and rgpF genes of pRGP1 were independently mutated by an internal deletion, and the LOS chemotypes of their transformants were examined. The transformant with an rgpA deletion showed the same LOS profile as E. coli without a plasmid. The transformant with an rgpB deletion showed the same LOS profile as E. coli harboring rgpA alone. The transformant with an rgpF deletion showed the LOS band with the most retarded migration. On the basis of these results, we speculated that RgpA, RgpB, and RgpF, in that order, function in rhamnan polymerization.

Characterization of Enterohemorrhagic Escherichia coli on Veal Hides and Carcasses

2016 ◽  
Vol 80 (1) ◽  
pp. 136-145 ◽  
Author(s):  
JOSEPH M. BOSILEVAC ◽  
RONG WANG ◽  
BRANDON E. LUEDTKE ◽  
SUSANNE HINKLEY ◽  
TOMMY L. WHEELER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Sample Collection ◽  
Foodborne Illnesses ◽  
Screening Assay ◽  
Department Of Agriculture ◽  
E Coli ◽  
Inspection Service ◽  
Collection Date

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin–producing E. coli associated with the most severe forms of foodborne illnesses. The U.S. Department of Agriculture, Food Safety and Inspection Service has identified a higher percentage of non-O157 EHEC compared with E. coli O157:H7–positive samples collected from veal trimmings than from products produced from other cattle slaughter classes. Therefore samples were collected from hides and preevisceration carcasses at five veal processors to assess E. coli O157:H7 and non-O157 EHEC contamination during bob veal and formula-fed veal dressing procedures. E. coli O157:H7 prevalence was measured by culture isolation and found to be on 20.3% of hides and 6.7% of carcasses. In contrast, a non-O157 EHEC molecular screening assay identified 90.3% of hides and 68.2% of carcasses as positive. Only carcass samples were taken forward to culture confirmation and 38.7% yielded one or more non-O157 EHEC isolates. The recovery of an EHEC varied by plant and sample collection date; values ranged from 2.1 to 87.8% among plants and from 4.2 to 64.2% within the same plant. Three plants were resampled after changes were made to sanitary dressing procedures. Between the two collection times at the three plants, hide-to-carcass transfer of E. coli O157:H7 and non-O157 EHEC was significantly reduced. All adulterant EHEC serogroups (O26, O45, O103, O111, O121, and O145) were isolated from veal carcasses as well as four other potentially pathogenic serogroups (O5, O84, O118, and O177). Bob veal was found to have a greater culture prevalence of E. coli O157:H7 and greater positive molecular screens for non-O157 EHEC than formula-fed veal (P < 0.05), but the percentage of culture-confirmed non-O157 EHEC was not different (P > 0.05) between the two types of calves. EHEC-O26, -O111, and -O121 were found more often in bob veal (P < 0.05), whereas EHEC-O103 was found more often in formula-fed veal (P < 0.05).

scholarly journals Presence and Characterization of a Mosaic Genomic Island Which Distinguishes Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:H− from E. coli O157:H7

2005 ◽  
Vol 71 (8) ◽  
pp. 4875-4878 ◽  
Author(s):  
Andreas Janka ◽  
Georg Becker ◽  
Anne-Katharina Sonntag ◽  
Martina Bielaszewska ◽  
Ulrich Dobrindt ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genomic Island ◽  
Enterohemorrhagic Escherichia Coli ◽  
Resistance Locus ◽  
Escherichia Coli O157 ◽  
Related Sequence ◽  
E Coli ◽  
Pcr Targeting

ABSTRACT A mosaic genomic island comprising Shigella resistance locus (SRL) sequences flanked by segments of Escherichia coli O157:H7 strain EDL933 O islands 43, 81, and 82 was identified in sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H− strain 493/89. This mosaic island is absent from strain EDL933. PCR targeting the SRL-related sequence is a useful tool to distinguish SF EHEC O157:H− from EHEC O157:H7.

scholarly journals Characterization of the Escherichia coli O157:H7 Sakai GadE Regulon

2008 ◽  
Vol 191 (6) ◽  
pp. 1868-1877 ◽  
Author(s):  
Sivapriya Kailasan Vanaja ◽  
Teresa M. Bergholz ◽  
Thomas S. Whittam
Keyword(s):  
Escherichia Coli ◽  
Growth Phase ◽  
Virulence Genes ◽  
Stationary Phases ◽  
Acid Resistance ◽  
Dependent Manner ◽  
E Coli ◽  
Transcription Profiles ◽  
Enterocyte Effacement

ABSTRACTIntegrating laterally acquired virulence genes into the backbone regulatory network is important for the pathogenesis ofEscherichia coliO157:H7, which has captured many virulence genes through horizontal transfer during evolution. GadE is an essential transcriptional activator of the glutamate decarboxylase (GAD) system, the most efficient acid resistance (AR) mechanism inE. coli. The full contribution of GadE to the AR and virulence ofE. coliO157:H7 remains largely unknown. We inactivatedgadEinE. coliO157:H7 Sakai and compared global transcription profiles of the mutant with that of the wild type in the exponential and stationary phases of growth. Inactivation ofgadEsignificantly altered the expression of 60 genes independently of the growth phase and of 122 genes in a growth phase-dependent manner. Inactivation ofgadEmarkedly downregulated the expression ofgadA, gadB, andgadCand of many acid fitness island genes. Nineteen genes encoded on the locus of enterocyte effacement (LEE), includingler, showed a significant increase in expression upongadEinactivation. Inactivation oflerin the ΔgadEstrain reversed the effect ofgadEdeletion on LEE expression, indicating that Ler is necessary for LEE repression by GadE. GadE is also involved in downregulation of LEE expression under conditions of moderately acidic pH. Characterization of AR of the ΔgadEstrain revealed that GadE is indispensable for a functional GAD system and for survival ofE. coliO157:H7 in a simulated gastric environment. Altogether, these data indicate that GadE is critical for the AR ofE. coliO157:H7 and that it plays an important role in virulence by downregulating expression of LEE.

scholarly journals Role of hha and ler in Transcriptional Regulation of the esp Operon of Enterohemorrhagic Escherichia coli O157:H7

2004 ◽  
Vol 186 (21) ◽  
pp. 7290-7301 ◽  
Author(s):  
Vijay K. Sharma ◽  
Richard L. Zuerner
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulation ◽  
Specific Binding ◽  
Transposon Mutagenesis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
Galactosidase Activity ◽  
Enterocyte Effacement ◽  
Transposon Insertions

ABSTRACT The locus of enterocyte effacement (LEE), which includes five major operons (LEE1 through LEE4 and tir), enables enterohemorrhagic Escherichia coli (EHEC) O157:H7 to produce attaching and effacing lesions on host cells. Expression of LEE2, LEE3, and tir is positively regulated by ler, a gene located in LEE1. Transcriptional regulation of the esp operon (LEE4), however, is not well defined. Transposon mutagenesis was used to identify transcriptional regulators of the esp operon by screening for mutants with increased β-galactosidase activity in an EHEC O157:H7 strain harboring an esp::lac transcriptional fusion. All mutants with significant increases in β-galactosidase activity had transposon insertions in hha (hha::Tn). Specific complementation of the hha::Tn mutation with a plasmid-encoded copy of hha reduced β-galactosidase activity to the level expressed in the parental esp::lac strain. Purified Hha, however, bound poorly to the esp promoter, suggesting that Hha might repress the transcription of a positive regulator of esp. Transposon mutagenesis of a Δhha esp::lac strain expressing elevated levels of β-galactosidase resulted in ler mutants with reduced β-galactosidase activity. Purified Hha bound to the ler promoter with a higher affinity, and complementation of a Δhha mutation in a Δhha ler::lac strain repressed β-galactosidase activity to the level expressed in a ler::lac strain. A positive regulatory role of ler in esp expression was demonstrated by specific binding of Ler to the esp promoter, reduced expression of β-galactosidase in Δler esp::lac strains with and without hha, and severalfold-increased transcription of ler and espA in strains lacking hha. These results indicate that hha-mediated repression of ler causes reduced expression of the esp operon.

Sign in / Sign up

Export Citation Format

Share Document