A gene cluster closely related to type II secretion pathway operons of Gram-negative bacteria is located on the large plasmid of enterohemorrhagic Escherichia coli O157 strains

ABSTRACT We report the identification of a set of Legionella pneumophila genes that encode products with homology to proteins of the type II general secretion pathway of gram-negative bacteria. A strain containing a deletion-substitution mutation of two of these genes was unable to secrete the Msp protease. This strain was unable to multiply within the free-living amoeba Acanthamoeba castellanii yet was able to kill HL-60-derived macrophages. Because Msp is not required for growth in amoebae, other proteins which are important for growth in amoebae are likely secreted by this pathway.

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Exchange of Xcp (Gsp) Secretion Machineries betweenPseudomonas aeruginosa and Pseudomonas alcaligenes: Species Specificity Unrelated to Substrate Recognition

Journal of Bacteriology ◽

10.1128/jb.183.3.959-967.2001 ◽

2001 ◽

Vol 183 (3) ◽

pp. 959-967 ◽

Cited By ~ 27

Author(s):

Arjan de Groot ◽

Margot Koster ◽

Manon Gérard-Vincent ◽

Gijs Gerritse ◽

Andrée Lazdunski ◽

...

Keyword(s):

Secretory Pathway ◽

Gram Negative Bacteria ◽

Gene Products ◽

Type Ii ◽

Gram Negative ◽

Secretion Pathway ◽

Heat Stable ◽

Pseudomonas Alcaligenes ◽

Mutant Complementation ◽

Species Specific

ABSTRACT Pseudomonas aeruginosa and Pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type II or general secretory pathway, which requires at least 12 xcp gene products (XcpA and XcpP to -Z). Despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. Based on results obtained with Erwinia, it has been proposed that the XcpP and/or XcpQ homologs determine this secretion specificity (M. Linderberg, G. P. Salmond, and A. Collmer, Mol. Microbiol. 20:175–190, 1996). In the present study, we report that XcpP and XcpQ of P. alcaligenes could not substitute for their respectiveP. aeruginosa counterparts. However, these complementation failures could not be correlated to species-specific recognition of exoproteins, since these bacteria could secrete exoproteins of each other. Moreover, when P. alcaligenes xcpP andxcpQ were expressed simultaneously in a P. aeruginosa xcpPQ deletion mutant, complementation was observed, albeit only on agar plates and not in liquid cultures. After growth in liquid culture the heat-stable P. alcaligenes XcpQ multimers were not detected, whereas monomers were clearly visible. Together, our results indicate that the assembly of a functional Xcp machinery requires species-specific interactions between XcpP and XcpQ and between XcpP or XcpQ and another, as yet uncharacterized component(s).

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Screening for Inhibitors of Acetaldehyde Dehydrogenase (AdhE) from Enterohemorrhagic Escherichia coli (EHEC)

SLAS DISCOVERY Advancing Life Sciences ◽

10.1177/2472555218768062 ◽

2018 ◽

Vol 23 (8) ◽

pp. 815-822

Author(s):

Caroline E. Zetterström ◽

Pia Uusitalo ◽

Weixing Qian ◽

Shannon Hinch ◽

Rémi Caraballo ◽

...

Keyword(s):

Escherichia Coli ◽

Antibacterial Agents ◽

Enterohemorrhagic Escherichia Coli ◽

Gram Negative Bacteria ◽

Acetaldehyde Dehydrogenase ◽

Gram Negative ◽

Starting Point ◽

Clear Dose Response ◽

Dose Response Effect ◽

Type Three Secretion

Acetaldehyde dehydrogenase (AdhE) is a bifunctional acetaldehyde–coenzyme A (CoA) dehydrogenase and alcohol dehydrogenase involved in anaerobic metabolism in gram-negative bacteria. This enzyme was recently found to be a key regulator of the type three secretion (T3S) system in Escherichia coli. AdhE inhibitors can be used as tools to study bacterial virulence and a starting point for discovery of novel antibacterial agents. We developed a robust enzymatic assay, based on the acetaldehyde-CoA dehydrogenase activity of AdhE using both absorption and fluorescence detection models (Z′ > 0.7). This assay was used to screen ~11,000 small molecules in 384-well format that resulted in three hits that were confirmed by resynthesis and validation. All three compounds are noncompetitive with respect to acetaldehyde and display a clear dose–response effect with hill slopes of 1–2. These new inhibitors will be used as chemical tools to study the interplay between metabolism and virulence and the role of AdhE in T3S regulation in gram-negative bacteria, and as starting points for the development of novel antibacterial agents.

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Detection of Escherichia coli O157:H7 and Salmonella enterica serotype Typhimurium based on cell elongation induced by beta-lactam antibiotics

The Analyst ◽

10.1039/c9an00569b ◽

2019 ◽

Vol 144 (15) ◽

pp. 4505-4512 ◽

Cited By ~ 3

Author(s):

Min Jia ◽

Zhaochen Liu ◽

Chuanchen Wu ◽

Zhen Zhang ◽

Luyao Ma ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Elongation ◽

Membrane Filtration ◽

Detection Method ◽

Bacteria Detection ◽

Escherichia Coli O157 ◽

Gram Negative Bacteria ◽

Beta Lactam ◽

Gram Negative ◽

Beta Lactam Antibiotics

A novel Gram-negative bacteria detection method based on cell elongation combined with membrane filtration and magnetic separation was established.

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Characterization of a Novel Microcin That Kills Enterohemorrhagic Escherichia coli O157:H7 and O26

Applied and Environmental Microbiology ◽

10.1128/aem.01067-12 ◽

2012 ◽

Vol 78 (18) ◽

pp. 6592-6599 ◽

Cited By ~ 25

Author(s):

Lauren J. Eberhart ◽

James R. Deringer ◽

Kelly A. Brayton ◽

Ashish A. Sawant ◽

Thomas E. Besser ◽

...

Keyword(s):

Escherichia Coli ◽

Enterohemorrhagic Escherichia Coli ◽

Logarithmic Phase ◽

Type I ◽

Escherichia Coli O157 ◽

Content Type ◽

E Coli ◽

Secretion Pathway ◽

Dependent Inhibition

ABSTRACTA novel phenotype was recently identified in which specific strains ofEscherichia coliinhibit competingE. colistrains via a mechanism that was designated “proximity-dependent inhibition” (PDI). PDI-expressing (PDI+)E. coliis known to inhibit susceptible (PDI−)E. colistrains, including several enterohemorrhagic (EHEC) and enterotoxigenic (ETEC)E. colistrains. In this study, every strain from a genetically diverse panel ofE. coliO157:H7 (n= 25) and additional strains ofE. coliserovar O26 were susceptible to the PDI phenotype. LIVE/DEAD staining was consistent with inhibition by killing of susceptible cells. Comparative genome analysis identified the genetic component of PDI, which is composed of a plasmid-borne (Incl1) operon encoding a putative microcin and associated genes for transport, immunity, and microcin activation. Transfer of the plasmid to a PDI−strain resulted in transfer of the phenotype, and deletion of the genes within the operon resulted in loss of the inhibition phenotype. Deletion of chromosomally encodedtolCalso resulted in loss of the inhibitory phenotype, and this confirmed that the putative microcin is most likely secreted via a type I secretion pathway. Deletion of an unrelated plasmid gene did not affect the PDI phenotype. Quantitative reverse transcription (RT)-PCR demonstrated that microcin expression is correlated with logarithmic-phase growth. The ability to inhibit a diversity ofE. colistrains indicates that this microcin may influence gut community composition and could be useful for control of important enteric pathogens.

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On the path to uncover the bacterial type II secretion system

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0204 ◽

2012 ◽

Vol 367 (1592) ◽

pp. 1059-1072 ◽

Cited By ~ 73

Author(s):

Badreddine Douzi ◽

Alain Filloux ◽

Romé Voulhoux

Keyword(s):

Protein Interactions ◽

Secretion System ◽

Target Cells ◽

Type Ii Secretion ◽

Gram Negative Bacteria ◽

Type Ii ◽

Protein Protein Interactions ◽

Gram Negative ◽

Extracellular Milieu ◽

Type Ii Secretion System

Gram-negative bacteria have evolved several secretory pathways to release enzymes or toxins into the surrounding environment or into the target cells. The type II secretion system (T2SS) is conserved in Gram-negative bacteria and involves a set of 12 to 16 different proteins. Components of the T2SS are located in both the inner and outer membranes where they assemble into a supramolecular complex spanning the bacterial envelope, also called the secreton. The T2SS substrates transiently go through the periplasm before they are translocated across the outer membrane and exposed to the extracellular milieu. The T2SS is unique in its ability to promote secretion of large and sometimes multimeric proteins that are folded in the periplasm. The present review describes recently identified protein–protein interactions together with structural and functional advances in the field that have contributed to improve our understanding on how the type II secretion apparatus assembles and on the role played by individual proteins of this highly sophisticated system.

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Novel Type of Fimbriae Encoded by the Large Plasmid of Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:H−

Infection and Immunity ◽

10.1128/iai.69.7.4447-4457.2001 ◽

2001 ◽

Vol 69 (7) ◽

pp. 4447-4457 ◽

Cited By ~ 80

Author(s):

Werner Brunder ◽

A. Salam Khan ◽

Jörg Hacker ◽

Helge Karch

Keyword(s):

Escherichia Coli ◽

Gene Cluster ◽

Enterohemorrhagic Escherichia Coli ◽

Plasmid Replication ◽

Escherichia Coli O157 ◽

E Coli ◽

Significant Homology ◽

Genes Encoding ◽

Uremic Syndrome ◽

Six Genes

ABSTRACT Sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H− have emerged as important causes of diarrheal diseases and the hemolytic-uremic syndrome in Germany. In this study, we characterized a 32-kb fragment of the plasmid of SF EHEC O157:H−, pSFO157, which differs markedly from plasmid pO157 of classical non-sorbitol-fermenting EHEC O157:H7. We found a cluster of six genes, termed sfpA,sfpH, sfpC, sfpD,sfpJ, and sfpG, which mediate mannose-resistant hemagglutination and the expression of fimbriae.sfp genes are similar to the pap genes, encoding P-fimbriae of uropathogenic E. coli, but thesfp cluster lacks homologues of genes encoding subunits of a tip fibrillum as well as regulatory genes. The major pilin, SfpA, despite its similarity to PapA, does not cluster together with known PapA alleles in a phylogenetic tree but is structurally related to the PmpA pilin of Proteus mirabilis. The putative adhesin gene sfpG, responsible for the hemagglutination phenotype, shows significant homology neither to papGnor to other known sequences. Sfp fimbriae are 3 to 5 nm in diameter, in contrast to P-fimbriae, which are 7 nm in diameter. PCR analyses showed that the sfp gene cluster is a characteristic of SF EHEC O157:H− strains and is not present in other EHEC isolates, diarrheagenic E. coli, or otherEnterobacteriaceae. The sfp gene cluster is flanked by two blocks of insertion sequences and an origin of plasmid replication, indicating that horizontal gene transfer may have contributed to the presence of Sfp fimbriae in SF EHEC O157:H−.

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