East1 toxin and its presence in a changing microbial world

Sousa, Cristina Paiva de

doi:10.1590/s1678-91992003000100002

Cited by 4 publications

(5 citation statements)

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“…Enteroinvasive Escherichia coli (EIEC) isolates cause dysentery in humans and are closely related to Shigella species with regard to their virulence, biochemical, genetic, and physiopathological properties ( 1 ). Bacillary dysentery is caused by four Shigella species or EIEC, and is characterized by abdominal cramps, fever, and stool that contains blood, mucus, and pus ( 2 ).…”

Section: Introductionmentioning

confidence: 99%

“…Bacillary dysentery is caused by four Shigella species or EIEC, and is characterized by abdominal cramps, fever, and stool that contains blood, mucus, and pus ( 2 ). Enteroinvasive E. coli may cause invasive inflammatory colitis and occasionally causes dysentery, but in most cases, EIEC isolates cause watery diarrhea indistinguishable from that due to other diarrheagenic E. coli strains ( 1 , 3 ). Several virulence factors associated with Shigella and EIEC pathogenesis have been characterized.…”

Section: Introductionmentioning

confidence: 99%

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Virulence Gene Profile and Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) of Enteroinvasive Escherichia coli (EIEC) Isolates From Patients With Diarrhea in Kerman, Iran

Hosseini-Nave

Mansouri

Moghadam

et al. 2016

Jundishapur J Microbiol

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BackgroundEnteroinvasive Escherichia coli (EIEC) isolates cause dysentery in humans. Several virulence factors associated with EIEC pathogenesis have been characterized. Multilocus variable-number tandem-repeat analysis (MLVA) is a PCR-based method that has been used for genotyping bacterial pathogens.ObjectivesThe aim of this study was to investigate the distribution of virulence factor genes in EIEC isolates from patients with diarrhea in Kerman, Iran, as well as the genetic relationships between these isolates.Patients and MethodsA total of 620 diarrheic stool samples were collected from patients attending two hospitals in Kerman from June 2013 to August 2014. All isolates were confirmed as EIEC by PCR for the ipaH gene. The EIEC isolates were evaluated by PCR for the presence of nine virulence genes (ial, set1A, sen, virF, invE, sat, sigA, pic, and sepA). MLVA was performed for all EIEC isolates.ResultsA total of 11 EIEC isolates were identified, and all were positive for the ial gene. The invE and virF genes were observed in 81.8% of the isolates, while sen, sigA, and pic were detected in 72.7%, 63.6%, and 27.3% of the isolates, respectively. None of the isolates were positive for the sat, set, and sepA genes. Using MLVA, the 11 total isolates were divided into five types.ConclusionsBy studying the profiles of virulence genes and MLVA, it can be concluded that EIEC isolates do not have high heterogeneity and are derived from a limited number of clones.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Virulence Gene Profile and Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) of Enteroinvasive Escherichia coli (EIEC) Isolates From Patients With Diarrhea in Kerman, Iran

Hosseini-Nave

Mansouri

Moghadam

et al. 2016

Jundishapur J Microbiol

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“…In sharp contrast, in prokaryotes only very few overlapping gene pairs are known. In the extremely well-researched Escherichia coli , as far as we know, only three overlapping gene pairs have been described: htgA / yaaW [ 22 , 23 ], yghW / morA [ 24 ], and tnpA / astA [ 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Evidence for the recent origin of a bacterial protein-coding, overlapping orphan gene by evolutionary overprinting

et al. 2015

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BackgroundGene duplication is believed to be the classical way to form novel genes, but overprinting may be an important alternative. Overprinting allows entirely novel proteins to evolve de novo, i.e., formerly non-coding open reading frames within functional genes become expressed. Only three cases have been described for Escherichia coli. Here, a fourth example is presented.ResultsRNA sequencing revealed an open reading frame weakly transcribed in cow dung, coding for 101 residues and embedded completely in the −2 reading frame of citC in enterohemorrhagic E. coli. This gene is designated novel overlapping gene, nog1. The promoter region fused to gfp exhibits specific activities and 5’ rapid amplification of cDNA ends indicated the transcriptional start 40-bp upstream of the start codon. nog1 was strand-specifically arrested in translation by a nonsense mutation silent in citC. This Nog1-mutant showed a phenotype in competitive growth against wild type in the presence of MgCl2. Small differences in metabolite concentrations were also found. Bioinformatic analyses propose Nog1 to be inner membrane-bound and to possess at least one membrane-spanning domain. A phylogenetic analysis suggests that the orphan gene nog1 arose by overprinting after Escherichia/Shigella separated from the other γ-proteobacteria.ConclusionsSince nog1 is of recent origin, non-essential, short, weakly expressed and only marginally involved in E. coli’s central metabolism, we propose that this gene is in an initial stage of evolution. While we present specific experimental evidence for the existence of a fourth overlapping gene in enterohemorrhagic E. coli, we believe that this may be an initial finding only and overlapping genes in bacteria may be more common than is currently assumed by microbiologists.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0558-z) contains supplementary material, which is available to authorized users.

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“…The overlapping gene pair htgA/yaaW from E. coli was considered to be overlapping, but htgA has been removed from the annotated genome due to conflicting data [17] , [18] . However, a plasmid-encoded gene from E. coli , tnpA , forms a transposase-like protein and contains astA , a heat stable enterotoxin [19] , [20] . In a close relative to E. coli , Shigella flexneri , the overlapping gene pair pic/setAB had been identified.…”

Section: Introductionmentioning

confidence: 99%

Predicting Statistical Properties of Open Reading Frames in Bacterial Genomes

et al. 2012

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An analytical model based on the statistical properties of Open Reading Frames (ORFs) of eubacterial genomes such as codon composition and sequence length of all reading frames was developed. This new model predicts the average length, maximum length as well as the length distribution of the ORFs of 70 species with GC contents varying between 21% and 74%. Furthermore, the number of annotated genes is predicted with high accordance. However, the ORF length distribution in the five alternative reading frames shows interesting deviations from the predicted distribution. In particular, long ORFs appear more often than expected statistically. The unexpected depletion of stop codons in these alternative open reading frames cannot completely be explained by a biased codon usage in the +1 frame. While it is unknown if the stop codon depletion has a biological function, it could be due to a protein coding capacity of alternative ORFs exerting a selection pressure which prevents the fixation of stop codon mutations. The comparison of the analytical model with bacterial genomes, therefore, leads to a hypothesis suggesting novel gene candidates which can now be investigated in subsequent wet lab experiments.

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East1 toxin and its presence in a changing microbial world

Cited by 4 publications

References 0 publications

Virulence Gene Profile and Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) of Enteroinvasive Escherichia coli (EIEC) Isolates From Patients With Diarrhea in Kerman, Iran

Virulence Gene Profile and Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) of Enteroinvasive Escherichia coli (EIEC) Isolates From Patients With Diarrhea in Kerman, Iran

Evidence for the recent origin of a bacterial protein-coding, overlapping orphan gene by evolutionary overprinting

Predicting Statistical Properties of Open Reading Frames in Bacterial Genomes

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