scholarly journals Mechanism of Nitrite Transporter NirC in Motility, Biofilm Formation, and Adhesion of Avian Pathogenic Escherichia Coli

2021 ◽  
Author(s):  
Jiaqi Liu ◽  
Dong Zhang ◽  
Siqi Lian ◽  
Xuanqiang Gu ◽  
Qianxi Hou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
High Performance ◽  
Gene Deletion ◽  
Biological Characteristics ◽  
Microvascular Endothelial Cell ◽  
Deficient Mutant ◽  
E Coli ◽  
Cyclic Diguanosine Monophosphate ◽  
Diguanosine Monophosphate

Abstract The Escherichia coli (E. coli) nirC gene encodes a nitrite transporter, which involved in transporting toxic nitrite (NO2-) from the environment into the bacteria. Although the deletion of nirC gene could cause changes in motility, adhesion in the previous study, and the virulence involved in the specified mechanism for pathogenic E. coli remains to be known. In the present work, we aimed to evaluate the role of NirC in a serotype O2:K1:H7 avian pathogenic Escherichia coli (APEC) strain. For this purpose, we generated a NirC-deficient mutant of APEC XM strain and examined its biological characteristics. The nirC gene deletion mutant enhanced ability of motility, decreased in biofilm formation, and it markedly reduced ability to adhere mouse brain microvascular endothelial cell b.End3 cells. For understanding its mechanism, sequentially we detected and found the stress regulator rpoS and its downstream genes csrA were up-regulated in NirC-deficient mutant while diguanylate cyclase gene dgcT was down-regulated. By high-performance liquid chromatography (HPLC) experiment, we demonstrated the concentration of intracellular 3',5'-cyclic diguanosine monophosphate (c-di-GMP) significantly decrease in nirC gene deletion mutant. Taken data together, we may make a conclusion with a possible signal pathway clue, due to NirC mutation, environmental NO2- accumulation leads to nitrite stress and inactivates c-di-GMP synthesis by stimulating the stress regulator RpoS, resulting in changes of biological characteristics.

Biodecomposition of Phenanthrene and Pyrene by a Genetically Engineered Escherichia coli

2020 ◽  
Vol 14 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Maryam Ahankoub ◽  
Gashtasb Mardani ◽  
Payam Ghasemi-Dehkordi ◽  
Ameneh Mehri-Ghahfarrokhi ◽  
Abbas Doosti ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Performance ◽  
Human Cancer ◽  
Genetically Engineered ◽  
Hazardous Substances ◽  
E Coli ◽  
Spiked Soil ◽  
Engineered Escherichia Coli ◽  
Genetically Manipulated ◽  
Hplc Measurement

Background: Genetically engineered microorganisms (GEMs) can be used for bioremediation of the biological pollutants into nonhazardous or less-hazardous substances, at lower cost. Polycyclic aromatic hydrocarbons (PAHs) are one of these contaminants that associated with a risk of human cancer development. Genetically engineered E. coli that encoded catechol 2,3- dioxygenase (C230) was created and investigated its ability to biodecomposition of phenanthrene and pyrene in spiked soil using high-performance liquid chromatography (HPLC) measurement. We revised patents documents relating to the use of GEMs for bioremediation. This approach have already been done in others studies although using other genes codifying for same catechol degradation approach. Objective: In this study, we investigated biodecomposition of phenanthrene and pyrene by a genetically engineered Escherichia coli. Methods: Briefly, following the cloning of C230 gene (nahH) into pUC18 vector and transformation into E. coli Top10F, the complementary tests, including catalase, oxidase and PCR were used as on isolated bacteria from spiked soil. Results: The results of HPLC measurement showed that in spiked soil containing engineered E. coli, biodegradation of phenanthrene and pyrene comparing to autoclaved soil that inoculated by wild type of E. coli and normal soil group with natural microbial flora, were statistically significant (p<0.05). Moreover, catalase test was positive while the oxidase tests were negative. Conclusion: These findings indicated that genetically manipulated E. coli can provide an effective clean-up process on PAH compounds and it is useful for bioremediation of environmental pollution with petrochemical products.

scholarly journals Label-free quantitative proteomic analysis of the inhibition effect of Lactobacillus rhamnosus GG on Escherichia coli biofilm formation in co-culture

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Huiyi Song ◽  
Ni Lou ◽  
Jianjun Liu ◽  
Hong Xiang ◽  
Dong Shang
Keyword(s):  
Escherichia Coli ◽  
Proteomic Analysis ◽  
Biofilm Formation ◽  
Lactobacillus Rhamnosus ◽  
Differentially Expressed ◽  
Differentially Expressed Proteins ◽  
Label Free ◽  
Quantitative Proteomic Analysis ◽  
E Coli ◽  
Protein Ubiquitination

Abstract Background Escherichia coli (E. coli) is the principal pathogen that causes biofilm formation. Biofilms are associated with infectious diseases and antibiotic resistance. This study employed proteomic analysis to identify differentially expressed proteins after coculture of E. coli with Lactobacillus rhamnosus GG (LGG) microcapsules. Methods To explore the relevant protein abundance changes after E. coli and LGG coculture, label-free quantitative proteomic analysis and qRT-PCR were applied to E. coli and LGG microcapsule groups before and after coculture, respectively. Results The proteomic analysis characterised a total of 1655 proteins in E. coli K12MG1655 and 1431 proteins in the LGG. After coculture treatment, there were 262 differentially expressed proteins in E. coli and 291 in LGG. Gene ontology analysis showed that the differentially expressed proteins were mainly related to cellular metabolism, the stress response, transcription and the cell membrane. A protein interaction network and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis indicated that the differentiated proteins were mainly involved in the protein ubiquitination pathway and mitochondrial dysfunction. Conclusions These findings indicated that LGG microcapsules may inhibit E. coli biofilm formation by disrupting metabolic processes, particularly in relation to energy metabolism and stimulus responses, both of which are critical for the growth of LGG. Together, these findings increase our understanding of the interactions between bacteria under coculture conditions.

Spheroplasts of enteropathogenic Escherichia coli. I. Biological characteristics

1968 ◽  
Vol 14 (6) ◽  
pp. 675-678 ◽  
Author(s):  
B. Diena ◽  
R. Wallace ◽  
L. Greenberg
Keyword(s):  
Escherichia Coli ◽  
Tissue Culture ◽  
Biological Characteristics ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli ◽  
O Antigen ◽  
Pathogenic Serotypes

The properties of glycine-induced spheroplasts of six pathogenic serotypes of E. coli were investigated. Fimbriae and flagella appeared to be only partially synthesized as was the somatic O antigen. Cytopathogenicity of these spheroplasts for tissue culture was reduced and the infection of the monolayers was retarded as compared with the normal bacillary forms. Sensitivity to phage was almost completely lost, suggesting that glycine had either interfered with the synthesis of phage receptors or had altered the mucopeptide layerwhich is the substrate for phage enzymes. Alternatively, the phage may become a prophage inside the spheroplast with the loss of virulence.

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

Microbiology ◽  
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.

scholarly journals Escherichia coli Harboring a Natural IncF Conjugative F Plasmid Develops Complex Mature Biofilms by Stimulating Synthesis of Colanic Acid and Curli

2008 ◽  
Vol 190 (22) ◽  
pp. 7479-7490 ◽  
Author(s):  
Thithiwat May ◽  
Satoshi Okabe
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Three Dimensional ◽  
F Plasmid ◽  
Form Complex ◽  
Global Regulators ◽  
E Coli ◽  
Colanic Acid ◽  
Regulatory Systems ◽  
Initial Deposition

ABSTRACT It has been shown that Escherichia coli harboring the derepressed IncFI and IncFII conjugative F plasmids form complex mature biofilms by using their F-pilus connections, whereas a plasmid-free strain forms only patchy biofilms. Therefore, in this study we investigated the contribution of a natural IncF conjugative F plasmid to the formation of E. coli biofilms. Unlike the presence of a derepressed F plasmid, the presence of a natural IncF F plasmid promoted biofilm formation by generating the cell-to-cell mating F pili between pairs of F+ cells (approximately two to four pili per cell) and by stimulating the formation of colanic acid and curli meshwork. Formation of colanic acid and curli was required after the initial deposition of F-pilus connections to generate a three-dimensional mushroom-type biofilm. In addition, we demonstrated that the conjugative factor of F plasmid, rather than a pilus synthesis function, was involved in curli production during biofilm formation, which promoted cell-surface interactions. Curli played an important role in the maturation process. Microarray experiments were performed to identify the genes involved in curli biosynthesis and regulation. The results suggested that a natural F plasmid was more likely an external activator that indirectly promoted curli production via bacterial regulatory systems (the EnvZ/OmpR two-component regulators and the RpoS and HN-S global regulators). These data provided new insights into the role of a natural F plasmid during the development of E. coli biofilms.

scholarly journals More than Enzymes That Make or Break Cyclic Di-GMP—Local Signaling in the Interactome of GGDEF/EAL Domain Proteins of Escherichia coli

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Olga Sarenko ◽  
Gisela Klauck ◽  
Franziska M. Wilke ◽  
Vanessa Pfiffer ◽  
Anja M. Richter ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Second Messenger ◽  
Bacterial Biofilm ◽  
Interaction Patterns ◽  
Systematic Analysis ◽  
E Coli ◽  
Diguanylate Cyclases ◽  
Hub Proteins ◽  
Effector Target

ABSTRACT The bacterial second messenger bis-(3′-5′)-cyclic diguanosine monophosphate (c-di-GMP) ubiquitously promotes bacterial biofilm formation. Intracellular pools of c-di-GMP seem to be dynamically negotiated by diguanylate cyclases (DGCs, with GGDEF domains) and specific phosphodiesterases (PDEs, with EAL or HD-GYP domains). Most bacterial species possess multiple DGCs and PDEs, often with surprisingly distinct and specific output functions. One explanation for such specificity is “local” c-di-GMP signaling, which is believed to involve direct interactions between specific DGC/PDE pairs and c-di-GMP-binding effector/target systems. Here we present a systematic analysis of direct protein interactions among all 29 GGDEF/EAL domain proteins of Escherichia coli . Since the effects of interactions depend on coexpression and stoichiometries, cellular levels of all GGDEF/EAL domain proteins were also quantified and found to vary dynamically along the growth cycle. Instead of detecting specific pairs of interacting DGCs and PDEs, we discovered a tightly interconnected protein network of a specific subset or “supermodule” of DGCs and PDEs with a coregulated core of five hyperconnected hub proteins. These include the DGC/PDE proteins representing the c-di-GMP switch that turns on biofilm matrix production in E. coli . Mutants lacking these core hub proteins show drastic biofilm-related phenotypes but no changes in cellular c-di-GMP levels. Overall, our results provide the basis for a novel model of local c-di-GMP signaling in which a single strongly expressed master PDE, PdeH, dynamically eradicates global effects of several DGCs by strongly draining the global c-di-GMP pool and thereby restricting these DGCs to serving as local c-di-GMP sources that activate specific colocalized effector/target systems. IMPORTANCE c-di-GMP signaling in bacteria is believed to occur via changes in cellular c-di-GMP levels controlled by antagonistic and potentially interacting pairs of diguanylate cyclases (DGCs) and c-di-GMP phosphodiesterases (PDEs). Our systematic analysis of protein-protein interaction patterns of all 29 GGDEF/EAL domain proteins of E. coli , together with our measurements of cellular c-di-GMP levels, challenges both aspects of this current concept. Knocking out distinct DGCs and PDEs has drastic effects on E. coli biofilm formation without changing the cellular c-di-GMP level. In addition, rather than generally coming in interacting DGC/PDE pairs, a subset of DGCs and PDEs operates as central interaction hubs in a larger "supermodule," with other DGCs and PDEs behaving as “lonely players” without contacts to other c-di-GMP-related enzymes. On the basis of these data, we propose a novel concept of “local” c-di-GMP signaling in bacteria with multiple enzymes that make or break the second messenger c-di-GMP.

scholarly journals The orientation of iron–sulphur clusters in membrane multilayers prepared from aerobically-grown Escherichia coli K12 and a cytochrome-deficient mutant

1980 ◽  
Vol 190 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Haywood Blum ◽  
Robert K. Poole ◽  
Tomoko Ohnishi
Keyword(s):  
Magnetic Field ◽  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Deficient Mutant ◽  
E Coli ◽  
Membrane Particles ◽  
Degree Of Orientation ◽  
High Degree ◽  
Cytochrome Content ◽  
The Magnetic Field

1. Membrane particles prepared from ultrasonically-disrupted, aerobically-grown Escherichia coli were centrifuged on to a plastic film that was supported perpendicular to the centrifugal field to yield oriented membrane multilayers. In such preparations, there is a high degree of orientation of the planes of the membranes such that they lie parallel to each other and to the supporting film. 2. When dithionite- or succinate-reduced multilayers are rotated in the magnetic field of an e.p.r. spectrometer, about an axis lying in the membrane plane, angular-dependent signals from an iron–sulphur cluster at gx=1.92, gy=1.93 and gz=2.02 are seen. The g=1.93 signal has maximal amplitude when the plane of the multilayer is perpendicular to the magnetic field. Conversely, the g=2.02 signal is maximal when the plane of the multilayer is parallel with the magnetic field. 3. Computer simulations of the experimental data show that the cluster lies in the cytoplasmic membrane with the gy axis perpendicular to the membrane plane and with the gx and gz axes lying in the membrane plane. 4. In partially-oxidized multilayers, a signal resembling the mitochondrial high-potential iron–sulphur protein (Hipip) is seen whose gz=2.02 axis may be deduced as lying perpendicular to the membrane plane. 5. Appropriate choice of sample temperature and receiver gain reveals two further signals in partially-reduced multilayers: a g=2.09 signal arises from a cluster with its gz axis in the membrane plane, whereas a g=2.04 signal is from a cluster with the gz axis lying along the membrane normal. 6. Membrane particles from a glucose-grown, haem-deficient mutant contain dramatically-lowered levels of cytochromes and exhibit, in addition to the iron–sulphur clusters seen in the parental strain, a major signal at g=1.90. 7. Only the latter may be demonstrated to be oriented in multilayer preparations from the mutant. 8. Comparisons are drawn between the orientations of the iron–sulphur proteins in the cytoplasmic membrane of E. coli and those in mitochondrial membranes. The effects of diminished cytochrome content on the properties of the iron–sulphur proteins are discussed.

scholarly journals Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Kelvin G. K. Goh ◽  
Danilo G. Moriel ◽  
Steven J. Hancock ◽  
Minh-Duy Phan ◽  
Mark A. Schembri
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Secretion System ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Type V Secretion ◽  
K 12 ◽  
Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli

2019 ◽  
Vol 65 (9) ◽  
pp. 691-702 ◽  
Author(s):  
Yi Gou ◽  
Weiqi Liu ◽  
Jing Jing Wang ◽  
Ling Tan ◽  
Bin Hong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Motility ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Signal Transmission ◽  
Bacterial Motility ◽  
Type I ◽  
E Coli ◽  
Real Time Quantitative Pcr ◽  
In The Wild

Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.

scholarly journals Flagellum-Mediated Mechanosensing and RflP Control Motility State of Pathogenic Escherichia coli

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Leanid Laganenka ◽  
María Esteban López ◽  
Remy Colin ◽  
Victor Sourjik
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Porous Medium ◽  
Biofilm Formation ◽  
Liquid Culture ◽  
Content Type ◽  
E Coli ◽  
Surface Contact ◽  
Conditional Inhibition ◽  
Flagellar Genes

ABSTRACT Bacterial flagellar motility plays an important role in many processes that occur at surfaces or in hydrogels, including adhesion, biofilm formation, and bacterium-host interactions. Consequently, expression of flagellar genes, as well as genes involved in biofilm formation and virulence, can be regulated by the surface contact. In a few bacterial species, flagella themselves are known to serve as mechanosensors, where an increased load on flagella experienced during surface contact or swimming in viscous media controls gene expression. In this study, we show that gene regulation by motility-dependent mechanosensing is common among pathogenic Escherichia coli strains. This regulatory mechanism requires flagellar rotation, and it enables pathogenic E. coli to repress flagellar genes at low loads in liquid culture, while activating motility in porous medium (soft agar) or upon surface contact. It also controls several other cellular functions, including metabolism and signaling. The mechanosensing response in pathogenic E. coli depends on the negative regulator of motility, RflP (YdiV), which inhibits basal expression of flagellar genes in liquid. While no conditional inhibition of flagellar gene expression in liquid and therefore no upregulation in porous medium was observed in the wild-type commensal or laboratory strains of E. coli, mechanosensitive regulation could be recovered by overexpression of RflP in the laboratory strain. We hypothesize that this conditional activation of flagellar genes in pathogenic E. coli reflects adaptation to the dual role played by flagella and motility during infection. IMPORTANCE Flagella and motility are widespread virulence factors among pathogenic bacteria. Motility enhances the initial host colonization, but the flagellum is a major antigen targeted by the host immune system. Here, we demonstrate that pathogenic E. coli strains employ a mechanosensory function of the flagellar motor to activate flagellar expression under high loads, while repressing it in liquid culture. We hypothesize that this mechanism allows pathogenic E. coli to regulate its motility dependent on the stage of infection, activating flagellar expression upon initial contact with the host epithelium, when motility is beneficial, but reducing it within the host to delay the immune response.

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