A Mechanistic Basis for Phosphoethanolamine Modification of the Cellulose Biofilm Matrix in Escherichia coli

Abstract The cellular response to DNA damage that has been most extensively studied is the SOS response of Escherichia coli. Analyses of the SOS response have led to new insights into the transcriptional and posttranslational regulation of processes that increase cell survival after DNA damage as well as insights into DNA-damage-induced mutagenesis, i.e., SOS mutagenesis. SOS mutagenesis requires the recA and umuDC gene products and has as its mechanistic basis the alteration of DNA polymerase III such that it becomes capable of replicating DNA containing miscoding and noncoding lesions. Ongoing investigations of the mechanisms underlying SOS mutagenesis, as well as recent observations suggesting that the umuDC operon may have a role in the regulation of the E. coli cell cycle after DNA damage has occurred, are discussed.

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Structural and Mechanistic Basis for the Inhibition of Escherichia coli RNA Polymerase by T7 Gp2

Molecular Cell ◽

10.1016/j.molcel.2012.06.013 ◽

2012 ◽

Vol 47 (5) ◽

pp. 755-766 ◽

Cited By ~ 33

Author(s):

Ellen James ◽

Minhao Liu ◽

Carol Sheppard ◽

Vladimir Mekler ◽

Beatriz Cámara ◽

...

Keyword(s):

Escherichia Coli ◽

Rna Polymerase ◽

Mechanistic Basis

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Genetic Analysis of the Chlamydomonas reinhadtii I-CreI Mobile Intron Homing System in Escherichia coli

Genetics ◽

10.1093/genetics/147.4.1653 ◽

1997 ◽

Vol 147 (4) ◽

pp. 1653-1664 ◽

Cited By ~ 3

Author(s):

Lenny M Seligman ◽

Kathryn M Stephens ◽

Jeremiah H Savage ◽

Raymond J Monnat

Keyword(s):

Escherichia Coli ◽

Translation Termination ◽

Homing Endonuclease ◽

Genetic Selection ◽

Functional Requirements ◽

Active Site Residues ◽

Mechanistic Basis ◽

Partial Activity ◽

Site Recognition

Abstract We have developed and used a genetic selection system in Escherichia coli to study functional requirements for homing site recognition and cleavage by a representative eukaryotic mobile intron endonuclease. The homing endonuclease, I-CreI, was originally isolated from the chloroplast of the unicellular green alga Chlamydomonas reinhardtii. I-CreI homing site mutants contained base pair substitutions or single base deletions that altered the rate of homing site cleavage and/or product release. I-CreI endonuclease mutants fell into six phenotypic classes that differed in in vivo activity, toxicity or genetic dominance. Inactivating mutations clustered in the N-terminal 60% of the I-CreI amino acid sequence, and two frameshift mutations were isolated that resulted in premature translation termination though retained partial activity. These mutations indicate that the N-terminal two-thirds of the I-CreI endonuclease is sufficient for homing site recognition and cleavage. Substitution mutations altered in four potential active site residues were examined D20N, Q47H or R70A substitutions inactivated endonuclease activity, whereas S22A did not. The genetic approach we have taken complements phylogenetic and structural studies of mobile intron endonucleases and has provided new information on the mechanistic basis of I-CreI homing site recognition and cleavage.

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Matrix-trapped viruses can prevent invasion of bacterial biofilms by colonizing cells

eLife ◽

10.7554/elife.65355 ◽

2021 ◽

Vol 10 ◽

Author(s):

Matthew C Bond ◽

Lucia Vidakovic ◽

Praveen K Singh ◽

Knut Drescher ◽

Carey D Nadell

Keyword(s):

Escherichia Coli ◽

Bacterial Biofilms ◽

Lytic Phage ◽

Prior Work ◽

Polymer Layers ◽

E Coli ◽

The Matrix ◽

Phage T7 ◽

Biofilm Matrix

Bacteriophages can be trapped in the matrix of bacterial biofilms, such that the cells inside them are protected. It is not known whether these phages are still infectious and whether they pose a threat to newly arriving bacteria. Here we address these questions using Escherichia coli and its lytic phage T7. Prior work has demonstrated that T7 phages are bound in the outermost curli polymer layers of the E. coli biofilm matrix. We show that these phages do remain viable and can kill colonizing cells that are T7-susceptible. If cells colonize a resident biofilm before phages do, we find that they can still be killed by phage exposure if it occurs soon thereafter. However, if colonizing cells are present on the biofilm long enough before phage exposure, they gain phage protection via envelopment within curli-producing clusters of the resident biofilm cells.

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TheNeisseria gonorrhoeaeBiofilm Matrix Contains DNA, and an Endogenous Nuclease Controls Its Incorporation

Infection and Immunity ◽

10.1128/iai.01162-10 ◽

2011 ◽

Vol 79 (4) ◽

pp. 1504-1511 ◽

Cited By ~ 42

Author(s):

Christopher T. Steichen ◽

Christine Cho ◽

Jian Q. Shao ◽

Michael A. Apicella

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Parent Strain ◽

Deletion Mutant ◽

Extracellular Dna ◽

Wild Type ◽

Multiple Forms ◽

Phenotypic Analysis ◽

Endogenous Nuclease ◽

Biofilm Matrix

ABSTRACTNeisseria gonorrhoeaehas been shown to produce biofilms both in experimental flow chambers and in the human host. Our laboratory has shown that extracellular DNA is an essential component of the gonococcal matrix. We have also identified a gene inN. gonorrhoeae, which we designatednuc. This gene has homology with the staphylococcus-secreted thermonuclease. Our laboratory has characterizednucthrough phenotypic analysis of anucdeletion mutant. Biofilms grown with this strain are significantly thicker and of greater biomass than theN. gonorrhoeae1291 parent strain. Confocal microscopy indicates that the increased size of the mutant biofilms appears to be due to elevated amounts of extracellular DNA in the biofilm matrix. Chromosomal complementation of thenucmutation restored the wild-type biofilm phenotype. In addition, we have cloned and expressed the Nuc protein inEscherichia coli, and our data indicate that it has the ability to digest multiple forms of DNA and is a thermonuclease. The ability of Nuc to digest DNA also extends to its ability to disrupt established gonococcal biofilms through degradation of the DNA in the biofilm matrix. Our studies indicate that theN. gonorrhoeaebiofilm contains DNA and that the Nuc protein appears to play a role in biofilm formation and remodeling.

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Impact of biofilm matrix components on interaction of commensal Escherichia coli with the gastrointestinal cell line HT-29

Cellular and Molecular Life Sciences ◽

10.1007/s00018-006-6222-4 ◽

2006 ◽

Vol 63 (19-20) ◽

pp. 2352-2363 ◽

Cited By ~ 58

Author(s):

X. Wang ◽

M. Rochon ◽

A. Lamprokostopoulou ◽

H. Lünsdorf ◽

M. Nimtz ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Line ◽

Matrix Components ◽

Ht 29 ◽

Biofilm Matrix

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The Effect of Disinfectants on Quinolone Resistant E. coli (QREC) in Biofilm

Microorganisms ◽

10.3390/microorganisms8111831 ◽

2020 ◽

Vol 8 (11) ◽

pp. 1831

Author(s):

Ane Mohr Osland ◽

Lene K. Vestby ◽

Live L. Nesse

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Bactericidal Effect ◽

E Coli ◽

Planktonic Bacteria ◽

Colony Forming Units ◽

Number Of Microorganisms ◽

Reduction Effect ◽

Susceptibility Tests ◽

Biofilm Matrix

The aim of disinfection is to reduce the number of microorganisms on surfaces which is a challenge due to biofilms. In the present study, six quinolone resistant Escherichia coli (QREC) strains with three different biofilm matrix compositions were included to assess the log10 colony forming units (CFU) reduction effect of three disinfectants at various exposure times on biofilm of different ages and morphotypes. Biofilm was formed on stainless steel coupons for two and five days before transferred to tubes with Virocid 0, 25%, VirkonS 1%, and TP990 1% and left for various exposure times. The biofilms were scraped off and serial dilutions were spread on blood agar plates where colony forming units (CFU) were counted. A mean log10 CFU reduction ≥4 was seen on two-day-old biofilm with VirkonS and Virocid (30 min) but not on five-day old biofilm. TP990 did not display sufficient effect under the conditions tested. The bactericidal effect was inferior to that reported on planktonic bacteria. The findings of this study should be considered when establishing both disinfectant routines and standard susceptibility tests, which further should accommodate E. coli biofilms and not only Pseudomonas as is the case today.

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Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081693 ◽

1978 ◽

Vol 36 (2) ◽

pp. 166-167 ◽

Cited By ~ 1

Author(s):

G. Stöffler ◽

R.W. Bald ◽

J. Dieckhoff ◽

H. Eckhard ◽

R. Lührmann ◽

...

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Ribosomal Proteins ◽

Structural Organization ◽

Three Dimensional ◽

Ribosomal Subunit ◽

Spatial Arrangement ◽

Small Subunit ◽

Antibody Binding ◽

Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

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Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060490 ◽

1967 ◽

Vol 25 ◽

pp. 96-97

Author(s):

Manfred E. Bayer

Keyword(s):

Escherichia Coli ◽

Cell Wall ◽

Electron Microscope ◽

Uranyl Acetate ◽

E Coli ◽

Receptor Sites ◽

Rigid Cell Wall ◽

Host Cell Surface ◽

Bacterial Viruses ◽

Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

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Infection of Escherichia coli with bacteriophages

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063767 ◽

1969 ◽

Vol 27 ◽

pp. 370-371

Author(s):

Manfred E. Bayer

Keyword(s):

Escherichia Coli ◽

Nucleic Acid ◽

Cell Surface ◽

Virus Type ◽

Infection Process ◽

Adsorption Site ◽

The Other ◽

Specific Receptors ◽

Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

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