scholarly journals A genetic screen to identify factors affected by undecaprenyl phosphate recycling uncovers novel connections to morphogenesis in Escherichia coli

2020 ◽  
Author(s):  
Matthew A. Jorgenson ◽  
Joseph C. Bryant
Keyword(s):  
Escherichia Coli ◽  
Genetic Screen ◽  
Undecaprenyl Phosphate

scholarly journals A genetic screen to identify factors affected by undecaprenyl phosphate recycling uncovers novel connections to morphogenesis in Escherichia coli

2020 ◽  
Author(s):  
Matthew A. Jorgenson ◽  
Joseph C. Bryant
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cytoplasmic Membrane ◽  
Response Regulator ◽  
Genetic Screen ◽  
Glutathione Metabolism ◽  
Cell Integrity ◽  
Two Component System ◽  
Dna Replication And Repair ◽  
Undecaprenyl Phosphate

AbstractUndecaprenyl phosphate (Und-P) is an essential lipid carrier that ferries cell wall intermediates across the cytoplasmic membrane in bacteria. Und-P is generated by dephosphorylating undecaprenyl diphosphate (Und-PP). In Escherichia coli, BacA, PgpB, YbjG, and LpxT dephosphorylate Und-PP and are conditionally essential. To identify vulnerabilities that arise when Und-P metabolism is defective, we developed a genetic screen for synthetic mutations in combination with ΔybjG ΔlpxT ΔbacA. The screen uncovered system-wide connections, including novel connections to cell division, DNA replication and repair, signal transduction, and glutathione metabolism. Further analysis revealed several new morphogenes; loss of one of these, qseC, caused cells to enlarge and lyse. QseC is the sensor kinase component of the QseBC two-component system. In the absence of QseC, the QseB response regulator is overactivated by PmrB cross-phosphorylation. Here, we show that deleting qseB completely reverses the shape defect of ΔqseC cells, as does overexpressing rprA (a small RNA). Surprisingly, deleting pmrB only partially suppressed qseC-related shape defects. Thus, QseB is activated by multiple factors in the absence of QseC and functions ascribed to QseBC may be related to cell wall defects. Altogether, our findings provide a framework for identifying new determinants of cell integrity that could be targeted in future therapies.

scholarly journals Mutant deletions in Escherichia coli affect the cellular levels of undecaprenyl phosphate and undecaprenyl diphosphate

2013 ◽  
Vol 13 (3) ◽  
pp. 86-91 ◽  
Author(s):  
Yuichiro Saito ◽  
Tatsuya Ishikawa ◽  
Marie Murakami ◽  
Keisuke Suzuki ◽  
Shingo Fujisaki
Keyword(s):  
Escherichia Coli ◽  
Undecaprenyl Phosphate

scholarly journals RpoS-Regulated Genes of Escherichia coli Identified by Random lacZ Fusion Mutagenesis

2004 ◽  
Vol 186 (24) ◽  
pp. 8499-8507 ◽  
Author(s):  
Somalinga R. V. Vijayakumar ◽  
Mark G. Kirchhof ◽  
Cheryl L. Patten ◽  
Herb E. Schellhorn
Keyword(s):  
Escherichia Coli ◽  
Sigma Factor ◽  
Genetic Screen ◽  
The Other ◽  
Alternative Sigma Factor ◽  
Gene Fusions ◽  
Wild Type ◽  
Stress Response Genes ◽  
Independent Gene ◽  
Bacterial Genes

ABSTRACT RpoS is a conserved alternative sigma factor that regulates the expression of many stress response genes in Escherichia coli. The RpoS regulon is large but has not yet been completely characterized. In this study, we report the identification of over 100 RpoS-dependent fusions in a genetic screen based on the differential expression of an operon-lacZ fusion bank in rpoS mutant and wild-type backgrounds. Forty-eight independent gene fusions were identified, including several in well-characterized RpoS-regulated genes, such as osmY, katE, and otsA. Many of the other fusions mapped to genes of unknown function or to genes that were not previously known to be under RpoS control. Based on the homology to other known bacterial genes, some of the RpoS-regulated genes of unknown functions are likely important in nutrient scavenging.

scholarly journals F1C Fimbriae Play an Important Role in Biofilm Formation and Intestinal Colonization by the Escherichia coli Commensal Strain Nissle 1917

2008 ◽  
Vol 75 (1) ◽  
pp. 246-251 ◽  
Author(s):  
Melissa A. Lasaro ◽  
Nina Salinger ◽  
Jing Zhang ◽  
Yantao Wang ◽  
Zhengtao Zhong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Genetic Screen ◽  
Bacterial Biofilm ◽  
Natural Environments ◽  
Intestinal Colonization ◽  
Human Gastrointestinal Tract ◽  
Infant Mouse ◽  
Commensal Strain ◽  
Inert Surface

ABSTRACT Bacterial biofilm formation is thought to enhance survival in natural environments and during interaction with hosts. A robust colonizer of the human gastrointestinal tract, Escherichia coli Nissle 1917, is widely employed in probiotic therapy. In this study, we performed a genetic screen to identify genes that are involved in Nissle biofilm formation. We found that F1C fimbriae are required for biofilm formation on an inert surface. In addition, these structures are also important for adherence to epithelial cells and persistence in infant mouse colonization. The data suggest a possible connection between Nissle biofilm formation and the survival of this commensal within the host. Further study of the requirements for robust biofilm formation may improve the therapeutic efficacy of Nissle 1917.

scholarly journals Discovery of New Genes Involved in Curli Production by a UropathogenicEscherichia coliStrain from the Highly Virulent O45:K1:H7 Lineage

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Nguyen Thi Khanh Nhu ◽  
Minh-Duy Phan ◽  
Kate M. Peters ◽  
Alvin W. Lo ◽  
Brian M. Forde ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Biofilm Formation ◽  
Genetic Screen ◽  
Neonatal Meningitis ◽  
Cationic Peptide ◽  
Amyloid Fibers ◽  
Content Type ◽  
Highly Virulent ◽  
Sessile Cells

ABSTRACTCurli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenicEscherichia coli(UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purinede novobiosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to asrcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation ofpurF(the first gene in the purine biosynthesis pathway) andrcpAalso led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis.IMPORTANCEUropathogenicEscherichia coli(UPEC) strains are the most common cause of urinary tract infection, a disease increasingly associated with escalating antibiotic resistance. UPEC strains possess multiple surface-associated factors that enable their colonization of the urinary tract, including fimbriae, curli, and autotransporters. Curli are extracellular amyloid fibers that enhance UPEC virulence and promote biofilm formation. Here we examined the function and regulation of curli in a UPEC pyelonephritis strain belonging to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. Curli expression at human physiological temperature led to increased biofilm formation, resistance of sessile cells to the human cationic peptide LL-37, and enhanced bladder colonization. Using a comprehensive genetic screen, we identified multiple genes involved in curli production, including several that were novel or poorly characterized with respect to curli synthesis. In total, this study demonstrates an important role for curli as a UPEC virulence factor that promotes biofilm formation, resistance, and pathogenesis.

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