Where To Begin? Mapping Transcription Start Sites Genome-Wide in Escherichia coli

A large part of our current understanding of gene regulation in Gram-positive bacteria is based on Bacillus subtilis , as it is one of the most well studied bacterial model systems. The rapid growth in data concerning its molecular and genomic biology is distributed across multiple annotation resources. Consequently, the interpretation of data from further B. subtilis experiments becomes increasingly challenging in both low- and large-scale analyses. Additionally, B. subtilis annotation of structured RNA and non-coding RNA (ncRNA), as well as the operon structure, is still lagging behind the annotation of the coding sequences. To address these challenges, we created the B. subtilis genome atlas, BSGatlas, which integrates and unifies multiple existing annotation resources. Compared to any of the individual resources, the BSGatlas contains twice as many ncRNAs, while improving the positional annotation for 70 % of the ncRNAs. Furthermore, we combined known transcription start and termination sites with lists of known co-transcribed gene sets to create a comprehensive transcript map. The combination with transcription start/termination site annotations resulted in 717 new sets of co-transcribed genes and 5335 untranslated regions (UTRs). In comparison to existing resources, the number of 5′ and 3′ UTRs increased nearly fivefold, and the number of internal UTRs doubled. The transcript map is organized in 2266 operons, which provides transcriptional annotation for 92 % of all genes in the genome compared to the at most 82 % by previous resources. We predicted an off-target-aware genome-wide library of CRISPR–Cas9 guide RNAs, which we also linked to polycistronic operons. We provide the BSGatlas in multiple forms: as a website (https://rth.dk/resources/bsgatlas/), an annotation hub for display in the UCSC genome browser, supplementary tables and standardized GFF3 format, which can be used in large scale -omics studies. By complementing existing resources, the BSGatlas supports analyses of the B. subtilis genome and its molecular biology with respect to not only non-coding genes but also genome-wide transcriptional relationships of all genes.

Download Full-text

Whole-Genome Sequencing Data for Serotyping Escherichia coli—It's Time for a Change!

Journal of Clinical Microbiology ◽

10.1128/jcm.01448-15 ◽

2015 ◽

Vol 53 (8) ◽

pp. 2402-2403 ◽

Cited By ~ 9

Author(s):

Claire Jenkins

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Whole Genome Sequencing Data ◽

Whole Genome ◽

Sequencing Data ◽

Content Type ◽

Link Type ◽

Article Type ◽

User Friendly

The accessibility of whole-genome sequencing (WGS) presents the opportunity for national reference laboratories to provide a state-of-the-art public health surveillance service. The replacement of traditional serology-based typing ofEscherichia coliby WGS is supported by user-friendly, freely available data analysis Web tools. Anarticle in this issueof theJournal of Clinical Microbiology(K. G. Joensen, A. M. M. Tetzschner, A. Iguchi, F. M. Aarestrup, and F. Scheutz, J Clin Microbiol, 53:2410–2426, 2015,http://dx.doi.org/10.1128/JCM.00008-15) describes SerotypeFinder, an essential guide to serotypingE. coliin the 21st century.

Download Full-text

Genome placement of alpha-haemolysin cluster is associated with alpha-haemolysin sequence variation, adhesin and iron acquisition factor profile of Escherichia coli

Microbial Genomics ◽

10.1099/mgen.0.000743 ◽

2021 ◽

Vol 7 (12) ◽

Author(s):

Rafał Kolenda ◽

Katarzyna Sidorczuk ◽

Mateusz Noszka ◽

Adrianna Aleksandrowicz ◽

Muhammad Moman Khan ◽

...

Keyword(s):

Escherichia Coli ◽

Type Species ◽

Sequence Variation ◽

Iron Acquisition ◽

Content Type ◽

E Coli ◽

Link Type ◽

Genome Wide ◽

High Prevalence ◽

Type 3

Since the discovery of haemolysis, many studies focused on a deeper understanding of this phenotype in Escherichia coli and its association with other virulence genes, diseases and pathogenic attributes/functions in the host. Our virulence-associated factor profiling and genome-wide association analysis of genomes of haemolytic and nonhaemolytic E. coli unveiled high prevalence of adhesins, iron acquisition genes and toxins in haemolytic bacteria. In the case of fimbriae with high prevalence, we analysed sequence variation of FimH, EcpD and CsgA, and showed that different adhesin variants were present in the analysed groups, indicating altered adhesive capabilities of haemolytic and nonhaemolytic E. coli . Analysis of over 1000 haemolytic E. coli genomes revealed that they are pathotypically, genetically and antigenically diverse, but their adhesin and iron acquisition repertoire is associated with genome placement of hlyCABD cluster. Haemolytic E. coli with chromosome-encoded alpha-haemolysin had high frequency of P, S, Auf fimbriae and multiple iron acquisition systems such as aerobactin, yersiniabactin, salmochelin, Fec, Sit, Bfd and hemin uptake systems. Haemolytic E. coli with plasmid-encoded alpha-haemolysin had similar adhesin profile to nonpathogenic E. coli, with high prevalence of Stg, Yra, Ygi, Ycb, Ybg, Ycf, Sfm, F9 fimbriae, Paa, Lda, intimin and type 3 secretion system encoding genes. Analysis of HlyCABD sequence variation revealed presence of variants associated with genome placement and pathotype.

Download Full-text

Genome-wide analysis in Escherichia coli unravels a high level of genetic homoplasy associated with cefotaxime resistance

Microbial Genomics ◽

10.1099/mgen.0.000556 ◽

2021 ◽

Vol 7 (4) ◽

Author(s):

Jordy P. M. Coolen ◽

Evert P. M. den Drijver ◽

Jaco J. Verweij ◽

Jodie A. Schildkraut ◽

Kornelia Neveling ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Type Species ◽

Whole Genome Sequencing Data ◽

Content Type ◽

E Coli ◽

Genome Wide Analysis ◽

Link Type ◽

Genome Wide ◽

Recurrent Mutations

Cefotaxime (CTX) is a third-generation cephalosporin (3GC) commonly used to treat infections caused by Escherichia coli . Two genetic mechanisms have been associated with 3GC resistance in E. coli . The first is the conjugative transfer of a plasmid harbouring antibiotic-resistance genes. The second is the introduction of mutations in the promoter region of the ampC β-lactamase gene that cause chromosome-encoded β-lactamase hyperproduction. A wide variety of promoter mutations related to AmpC hyperproduction have been described. However, their link to CTX resistance has not been reported. We recultured 172 cefoxitin-resistant E. coli isolates with known CTX minimum inhibitory concentrations and performed genome-wide analysis of homoplastic mutations associated with CTX resistance by comparing Illumina whole-genome sequencing data of all isolates to a PacBio sequenced reference chromosome. We mapped the mutations on the reference chromosome and determined their occurrence in the phylogeny, revealing extreme homoplasy at the −42 position of the ampC promoter. The 24 occurrences of a T at the −42 position rather than the wild-type C, resulted from 18 independent C>T mutations in five phylogroups. The −42 C>T mutation was only observed in E. coli lacking a plasmid-encoded ampC gene. The association of the −42 C>T mutation with CTX resistance was confirmed to be significant (false discovery rate <0.05). To conclude, genome-wide analysis of homoplasy in combination with CTX resistance identifies the −42 C>T mutation of the ampC promotor as significantly associated with CTX resistance and underlines the role of recurrent mutations in the spread of antibiotic resistance.

Download Full-text

Death by Cystine: an Adverse Emergent Property from a Beneficial Series of Reactions

Journal of Bacteriology ◽

10.1128/jb.00546-15 ◽

2015 ◽

Vol 197 (23) ◽

pp. 3626-3628 ◽

Cited By ~ 4

Author(s):

Larry Reitzer

Keyword(s):

Oxidative Stress ◽

Escherichia Coli ◽

Sulfur Metabolism ◽

Emergent Property ◽

Futile Cycle ◽

Content Type ◽

Link Type

In this issue of theJournal of Bacteriology, Chonoles Imlay et al. (K. R. Chonoles Imlay, S. Korshunov, and J. A. Imlay, J Bacteriol 197:3629–3644, 2015,http://dx.doi.org/10.1128/JB.00277-15) show that oxidative stress kills sulfur-restrictedEscherichia coligrown with sublethal H2O2when challenged with cystine. Killing requires rapid and seemingly unregulated cystine transport and equally rapid cystine reduction to cysteine. Cysteine export completes an energy-depleting futile cycle. Each reaction of the cycle could be beneficial. Together, a cystine-mediated vulnerability emerges during the transition from a sulfur-restricted to a sulfur-replete environment, perhaps because of complexities of sulfur metabolism.

Download Full-text

Genome-Wide Identification of Transcription Start Sites, Promoters and Transcription Factor Binding Sites in E. coli

PLoS ONE ◽

10.1371/journal.pone.0007526 ◽

2009 ◽

Vol 4 (10) ◽

pp. e7526 ◽

Cited By ~ 184

Author(s):

Alfredo Mendoza-Vargas ◽

Leticia Olvera ◽

Maricela Olvera ◽

Ricardo Grande ◽

Leticia Vega-Alvarado ◽

...

Keyword(s):

Transcription Factor ◽

Binding Sites ◽

Transcription Factor Binding Sites ◽

Transcription Factor Binding ◽

Transcription Start ◽

Transcription Start Sites ◽

E Coli ◽

Factor Binding ◽

Genome Wide

Download Full-text

Pathovar Transcriptomes

mSystems ◽

10.1128/msystems.00049-17 ◽

2017 ◽

Vol 2 (4) ◽

Cited By ~ 1

Author(s):

Amy Platenkamp ◽

Jay L. Mellies

Keyword(s):

Gene Expression ◽

Escherichia Coli ◽

Regulatory Networks ◽

Virulence Gene ◽

Model System ◽

Genomic Sequences ◽

Bacterial Strains ◽

Content Type ◽

Virulence Gene Expression ◽

Link Type

ABSTRACT Archetypal pathogenic bacterial strains are often used to elucidate regulatory networks of an entire pathovar, which encompasses multiple lineages and phylogroups. With enteropathogenic Escherichia coli (EPEC) as a model system, Hazen and colleagues (mSystems 6:e00024-17, 2017, https://doi.org/10.1128/mSystems.00024-17 ) used 9 isolates representing 8 lineages and 3 phylogroups to find that isolates with similar genomic sequences exhibit similarities in global transcriptomes under conditions of growth in medium that induces virulence gene expression, and they found variation among individual isolates. Archetypal pathogenic bacterial strains are often used to elucidate regulatory networks of an entire pathovar, which encompasses multiple lineages and phylogroups. With enteropathogenic Escherichia coli (EPEC) as a model system, Hazen and colleagues (mSystems 6:e00024-17, 2017, https://doi.org/10.1128/mSystems.00024-17 ) used 9 isolates representing 8 lineages and 3 phylogroups to find that isolates with similar genomic sequences exhibit similarities in global transcriptomes under conditions of growth in medium that induces virulence gene expression. They also found variation among individual isolates. Their work illustrates the importance of moving beyond observing regulatory phenomena of a limited number of regulons in a few archetypal strains, with the possibility of correlating clinical symptoms to key transcriptional pathways across lineages and phylogroups.

Download Full-text

Genome analysis reveals that the correct name of type strain Adlercreutzia caecicola DSM 22242T is Parvibacter caecicola Clavel et al. 2013

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijsem.0.004814 ◽

2021 ◽

Vol 71 (5) ◽

Author(s):

Dominic A. Stoll ◽

Nicolas Danylec ◽

Christina Grimmler ◽

Sabine E. Kulling ◽

Melanie Huch

Keyword(s):

Type Strain ◽

Type Species ◽

Draft Genome ◽

Amino Acid Identity ◽

Average Nucleotide Identity ◽

Content Type ◽

Link Type ◽

Genome Wide ◽

Average Amino Acid Identity ◽

Biochemical Analyses

The strain Adlercreutzia caecicola DSM 22242T (=CCUG 57646T=NR06T) was taxonomically described in 2013 and named as Parvibacter caecicola Clavel et al. 2013. In 2018, the name of the strain DSM 22242T was changed to Adlercreutzia caecicola (Clavel et al. 2013) Nouioui et al. 2018 due to taxonomic investigations of the closely related genera Adlercreutzia, Asaccharobacter and Enterorhabdus within the phylum Actinobacteria . However, the first whole draft genome of strain DSM 22242T was published by our group in 2019. Therefore, the genome was not available within the study of Nouioui et al. (2018). The results of the polyphasic approach within this study, including phenotypic and biochemical analyses and genome-based taxonomic investigations [genome-wide average nucleotide identity (gANI), alignment fraction (AF), average amino acid identity (AAI), percentage of orthologous conserved proteins (POCP) and genome blast distance phylogeny (GBDP) tree], indicated that the proposed change of the name Parvibacter caecicola to Adlercreutzia caecicola was not correct. Therefore, it is proposed that the correct name of Adlercreutzia caecicola (Clavel et al. 2013) Nouioui et al. 2018 strain DSM 22242T is Parvibacter caecicola Clavel et al. 2013.

Download Full-text

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽

10.1099/mic.0.001031 ◽

2021 ◽

Vol 167 (3) ◽

Author(s):

Sathi Mallick ◽

Shanti Kiran ◽

Tapas Kumar Maiti ◽

Anindya S. Ghosh

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Type Species ◽

Pentose Phosphate ◽

Bacterial Cells ◽

Surface Adhesion ◽

Content Type ◽

Penicillin Binding Proteins ◽

E Coli ◽

Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

Download Full-text