scholarly journals Insight into the molecular mechanism of miR-192 regulating Escherichia coli resistance in piglets

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Li Sun ◽  
Sen Wu ◽  
Chao-Hui Dai ◽  
Shou-Yong Sun ◽  
Guo-Qiang Zhu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanism ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Transcription Activator ◽  
E Coli ◽  
Cellular Processes ◽  
Adhesion Ability ◽  
The Relationship

MicroRNAs (miRNAs) have important roles in many cellular processes, including cell proliferation, growth and development, and disease control. Previous study demonstrated that the expression of two highly homologous miRNAs (miR-192 and miR-215) was up-regulated in weaned piglets with Escherichia coli F18 infection. However, the potential molecular mechanism of miR-192 in regulating E. coli infection remains unclear in pigs. In the present study, we analyzed the relationship between level of miR-192 and degree of E. coli resistance using transcription activator-like effector nuclease (TALEN), in vitro bacterial adhesion assays, and target genes research. A TALEN expression vector that specifically recognizes the pig miR-192 was constructed and then monoclonal epithelial cells defective in miR-192 were established. We found that miR-192 knockout led to enhance the adhesion ability of the E. coli strains F18ab, F18ac and K88ac, meanwhile increase the expression of target genes (DLG5 and ALCAM) by qPCR and Western blotting analysis. The results suggested that miR-192 and its key target genes (DLG5 and ALCAM) could have a key role in E. coli infection. Based on our findings, we propose that further investigation of miR-192 function is likely to lead to insights into the molecular mechanisms of E. coli infection.

scholarly journals Investigation of Transcription Repression and Small-Molecule Responsiveness by TetR-Like Transcription Factors Using a Heterologous Escherichia coli-Based Assay

2007 ◽  
Vol 189 (18) ◽  
pp. 6655-6664 ◽  
Author(s):  
Sang Kyun Ahn ◽  
Kapil Tahlan ◽  
Zhou Yu ◽  
Justin Nodwell
Keyword(s):  
Escherichia Coli ◽  
Transcription Factors ◽  
Small Molecule ◽  
Target Genes ◽  
Streptomyces Coelicolor ◽  
Targeted Mutagenesis ◽  
E Coli ◽  
Small Molecule Ligands

ABSTRACT The SCO7222 protein and ActR are two of ∼150 TetR-like transcription factors encoded in the Streptomyces coelicolor genome. Using bioluminescence as a readout, we have developed Escherichia coli-based biosensors that accurately report the regulatory activity of these proteins and used it to investigate their interactions with DNA and small-molecule ligands. We found that the SCO7222 protein and ActR repress the expression of their putative target genes, SCO7223 and actII-ORF2 (actA), respectively, by interacting with operator sequence in the promoters. The operators recognized by the two proteins are related such that O 7223 (an operator for SCO7223) could be bound by both the SCO7222 protein and ActR with similar affinities. In contrast, Oact (an operator for actII-ORF2) was bound tightly by ActR and more weakly by the SCO7222 protein. We demonstrated ligand specificity of these proteins by showing that while TetR (but not ActR or the SCO7222 protein) interacts with tetracyclines, ActR (but not TetR or the SCO7222 protein) interacts with actinorhodin and related molecules. Through operator-targeted mutagenesis, we found that at least two nucleotide changes in O 7223 were required to disrupt its interaction with SCO7222 protein, while ActR was more sensitive to changes on Oact . Most importantly, we found that the interaction of each protein with wild-type and mutant operator sequences in vivo and in vitro correlated perfectly. Our data suggest that E. coli-based biosensors of this type should be broadly applicable to TetR-like transcription factors.

scholarly journals Role of F1C Fimbriae, Flagella, and Secreted Bacterial Components in the Inhibitory Effect of Probiotic Escherichia coli Nissle 1917 on Atypical Enteropathogenic E. coli Infection

2014 ◽  
Vol 82 (5) ◽  
pp. 1801-1812 ◽  
Author(s):  
Sylvia Kleta ◽  
Marcel Nordhoff ◽  
Karsten Tedin ◽  
Lothar H. Wieler ◽  
Rafal Kolenda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Host Cells ◽  
Single Infection ◽  
Content Type ◽  
E Coli ◽  
Initial Adhesion

ABSTRACTEnteropathogenicEscherichia coli(EPEC) is recognized as an important intestinal pathogen that frequently causes acute and persistent diarrhea in humans and animals. The use of probiotic bacteria to prevent diarrhea is gaining increasing interest. The probioticE. colistrain Nissle 1917 (EcN) is known to be effective in the treatment of several gastrointestinal disorders. While bothin vitroandin vivostudies have described strong inhibitory effects of EcN on enteropathogenic bacteria, including pathogenicE. coli, the underlying molecular mechanisms remain largely unknown. In this study, we examined the inhibitory effect of EcN on infections of porcine intestinal epithelial cells with atypical enteropathogenicE. coli(aEPEC) with respect to single infection steps, including adhesion, microcolony formation, and the attaching and effacing phenotype. We show that EcN drastically reduced the infection efficiencies of aEPEC by inhibiting bacterial adhesion and growth of microcolonies, but not the attaching and effacing of adherent bacteria. The inhibitory effect correlated with EcN adhesion capacities and was predominantly mediated by F1C fimbriae, but also by H1 flagella, which served as bridges between EcN cells. Furthermore, EcN seemed to interfere with the initial adhesion of aEPEC to host cells by secretion of inhibitory components. These components do not appear to be specific to EcN, but we propose that the strong adhesion capacities enable EcN to secrete sufficient local concentrations of the inhibitory factors. The results of this study are consistent with a mode of action whereby EcN inhibits secretion of virulence-associated proteins of EPEC, but not their expression.

scholarly journals Expression of the Fluoroquinolones Efflux Pump Genes acrA and mdfA in Urinary Escherichia coli Isolates

2017 ◽  
Vol 66 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Sarah M. Abdelhamid ◽  
Rania R. Abozahra
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Efflux System ◽  
E Coli ◽  
Reverse Transcription Pcr ◽  
Tract Infections

Escherichia coli is one of the most frequent causes of urinary tract infections. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. Our aim in this study was to investigate the relation between antibiotic resistance and the expression of the efflux pump genes acrA and mdfA in E. coli by real-time reverse transcription-PCR. We tested the in vitro susceptibilities to 12 antibiotics in 28 clinical isolates of E. coli obtained from urine samples. We also determined the minimum inhibitory concentrations of levofloxacin to these samples. We then revealed significant correlations between the overexpression of both mdfA and acrA and MICs of levofloxacin. In conclusion, we demonstrated that the increased expression of efflux pump genes such as mdfA and acrA can lead to levofloxacin resistance in E. coli. These findings contribute to further understanding of the molecular mechanisms of efflux pump systems and how they contribute to antibiotic resistance.

scholarly journals Single-Target Regulators Constitute the Minority Group of Transcription Factors in Escherichia coli K-12

2021 ◽  
Vol 12 ◽  
Author(s):  
Tomohiro Shimada ◽  
Hiroshi Ogasawara ◽  
Ikki Kobayashi ◽  
Naoki Kobayashi ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Transcription Factors ◽  
Binding Sites ◽  
Target Genes ◽  
Minority Group ◽  
E Coli ◽  
Single Target ◽  
K 12

The identification of regulatory targets of all transcription factors (TFs) is critical for understanding the entire network of genome regulation. A total of approximately 300 TFs exist in the model prokaryote Escherichia coli K-12, but the identification of whole sets of their direct targets is impossible with use of in vivo approaches. For this end, the most direct and quick approach is to identify the TF-binding sites in vitro on the genome. We then developed and utilized the gSELEX screening system in vitro for identification of more than 150 E. coli TF-binding sites along the E. coli genome. Based on the number of predicted regulatory targets, we classified E. coli K-12 TFs into four groups, altogether forming a hierarchy ranging from a single-target TF (ST-TF) to local TFs, global TFs, and nucleoid-associated TFs controlling as many as 1,000 targets. Using the collection of purified TFs and a library of genome DNA segments from a single and the same E. coli K-12, we identified here a total of 11 novel ST-TFs, CsqR, CusR, HprR, NorR, PepA, PutA, QseA, RspR, UvrY, ZraR, and YqhC. The regulation of single-target promoters was analyzed in details for the hitherto uncharacterized QseA and RspR. In most cases, the ST-TF gene and its regulatory target genes are adjacently located on the E. coli K-12 genome, implying their simultaneous transfer in the course of genome evolution. The newly identified 11 ST-TFs and the total of 13 hitherto identified altogether constitute the minority group of TFs in E. coli K-12.

scholarly journals Gain of Spontaneous clpX Mutations Boosting Motility via Adaption to Environments in Escherichia coli

2021 ◽  
Vol 9 ◽  
Author(s):  
Bingyu Li ◽  
Chaofan Hou ◽  
Xian Ju ◽  
Yong Feng ◽  
Zhi-Qiang Ye ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Promoter Region ◽  
Molecular Mechanisms ◽  
Soft Agar ◽  
Transcriptional Level ◽  
E Coli ◽  
Proteomic Data ◽  
C Terminus ◽  
Enhanced Expression

Motility is finely regulated and is crucial to bacterial processes including colonization and biofilm formation. There is a trade-off between motility and growth in bacteria with molecular mechanisms not fully understood. Hypermotile Escherichia coli could be isolated by evolving non-motile cells on soft agar plates. Most of the isolates carried mutations located upstream of the flhDC promoter region, which upregulate the transcriptional expression of the master regulator of the flagellum biosynthesis, FlhDC. Here, we identified that spontaneous mutations in clpX boosted the motility of E. coli largely, inducing several folds of changes in swimming speed. Among the mutations identified, we further elucidated the molecular mechanism underlying the ClpXV78F mutation on the regulation of E. coli motility. We found that the V78F mutation affected ATP binding to ClpX, resulting in the inability of the mutated ClpXP protease to degrade FlhD as indicated by both structure modeling and in vitro protein degradation assays. Moreover, our proteomic data indicated that the ClpXV78F mutation elevated the stability of known ClpXP targets to various degrees with FlhD as one of the most affected. In addition, the specific tag at the C-terminus of FlhD being recognized for ClpXP degradation was identified. Finally, our transcriptome data characterized that the enhanced expression of the motility genes in the ClpXV78F mutations was intrinsically accompanied by the reduced expression of stress resistance genes relating to the reduced fitness of the hypermotile strains. A similar pattern was observed for previously isolated hypermotile E. coli strains showing high expression of flhDC at the transcriptional level. Hence, clpX appears to be a hot locus comparable to the upstream of the flhDC promoter region evolved to boost bacterial motility, and our finding provides insight into the reduced fitness of the hypermotile bacteria.

Inhibition effect of kaolinite on the development of antibiotic resistance genes in Escherichia coli induced by sublethal ampicillin and its molecular mechanism

2019 ◽  
Vol 16 (5) ◽  
pp. 347 ◽  
Author(s):  
Xiaolin Lai ◽  
Pingxiao Wu ◽  
Bo Ruan ◽  
Juan Liu ◽  
Zehua Liu ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Natural Environment ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Antibiotic Resistance Genes ◽  
E Coli

Environmental contextAntibiotic resistance by microorganisms in the natural environment poses a threat to ecosystems and public health. We report findings suggesting kaolinite can effectively inhibit the development of antibiotic resistance genes in microorganisms, and present a new understanding of the molecular mechanisms that promote the development of antibiotic resistance. These results are critical to mitigating environmental and public health risks resulting from the abuse of antibiotics. AbstractAntibiotic resistance and antibiotic resistance genes (ARGs) in the natural environment pose a threat to ecosystems and public health; therefore, better strategies are needed to mitigate the emergence of resistance. This study examined the expression of ARGs in Escherichia coli (E. coli) after exposure to sub-MIC (minimum inhibitory concentration) antibiotics for 15 days in the presence and absence of kaolinite. The results of the real-time polymerase chain reaction (PCR) showed that the expression levels of the eight target genes of E. coli adhering to kaolinite were relatively decreased, and the MIC results also indicated that the final resistance was lower than that of the strains without kaolinite. A close relationship between E. coli and kaolinite was also revealed, as well as a unique interfacial interaction. In addition, the differential protein expression was further analysed to detect proteins and genes associated with ARGs mutations, and then the underlying mechanisms of cell growth and metabolism were identified under low dose ampicillin stress to elucidate the role of kaolinite in the process. Molecular mechanisms analysis determined that when cells adhering to kaolinite were stressed, transport of ampicillin to the periplasmic space was reduced, and the redox metabolism of bacteria was promoted to combat the harsh environment. Moreover, cells synthesised related peptides or proteins under the action of ribosomal proteins to prevent toxic damage. Therefore, this work not only provides new insights into the cellular response to antibiotic stress, but also provides a topic for more research on methods to delay the emergence of ARGs.

scholarly journals Antibiotic resistance in Escherichia coli causing generalized infections in chickens in the UK in 1982: the relationship between the results of in vitro and in vivo furazolidone sensitivity tests

1984 ◽  
Vol 93 (3) ◽  
pp. 445-453 ◽  
Author(s):  
H. Williams Smith ◽  
M. A. Lovell
Keyword(s):  
Escherichia Coli ◽  
Laboratory Tests ◽  
Tetracycline Resistance ◽  
E Coli ◽  
Sensitivity Tests ◽  
Similar Survey ◽  
The Uk ◽  
The Relationship

SummaryCompared with a similar survey conducted ten years previously, a survey conducted in 1982, eleven years after the implementation of legislation forbidding the routine use of feeds containing ‘therapeutic’ antibiotics, revealed a decreased incidence of resistance to tetracyclines, furazolidone and sulphonamides in Escherichia coli strains causing generalized infections in chickens in the UK; the decrease was particularly marked in the case of tetracycline resistance, 17·9% of strains in 1982 being resistant to this antibiotic compared with 31·2% in 1972.Giving furazolidone to groups of chickens inoculated intramuscularly with O2:K1 strains of E. coli of differing degrees of furazolidone sensitivity indicated that great care is required in the performance and interpretation of laboratory tests for sensitivity to this antibiotic. Infections caused by strains that required as little as 1·25 μg/ml of furazolidone to inhibit their multiplication in laboratory tests responded poorly to furazolidone treatment; those that were inhibited by less responded well, better than to treatment with tetrac3rcline, chloramphenicol. ampicillin or trimethoprim.

An Endonuclease for Depurinated DNA in Escherichia coli B

1972 ◽  
Vol 50 (2) ◽  
pp. 217-224 ◽  
Author(s):  
W. G. Verly ◽  
Y. Paquette
Keyword(s):  
Escherichia Coli ◽  
B Cells ◽  
Molecular Mechanism ◽  
Alkylating Agents ◽  
Repair Enzyme ◽  
E Coli ◽  
Escherichia Coli B

Escherichia coli B cells contain an endonuclease which hydrolyzes apurinic sites in DNA. The enzyme has been demonstrated in vitro by the action of E. coli B41 proteins on depurinated DNA. This endonuclease probably plays a role in the molecular mechanism of the delayed inactivation of the T7 coliphage treated by monofunctional alkylating agents, which has been shown to be dependent on depurination; this endonuclease could also be a repair enzyme necessary for the first step of the repair of DNA containing apurinic sites.

scholarly journals The Bacteriophage T4 Transcription Activator MotA Interacts with the Far-C-Terminal Region of the σ70 Subunit of Escherichia coli RNA Polymerase

2002 ◽  
Vol 184 (14) ◽  
pp. 3957-3964 ◽  
Author(s):  
Suchira Pande ◽  
Anna Makela ◽  
Simon L. Dove ◽  
Bryce E. Nickels ◽  
Ann Hochschild ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Bacteriophage T4 ◽  
In Vitro Transcription ◽  
Terminal Region ◽  
Transcription Activator ◽  
E Coli ◽  
Terminal Amino ◽  
Two Hybrid

ABSTRACT Transcription from bacteriophage T4 middle promoters uses Escherichia coli RNA polymerase together with the T4 transcriptional activator MotA and the T4 coactivator AsiA. AsiA binds tightly within the C-terminal portion of the σ70 subunit of RNA polymerase, while MotA binds to the 9-bp MotA box motif, which is centered at −30, and also interacts with σ70. We show here that the N-terminal half of MotA (MotANTD), which is thought to include the activation domain, interacts with the C-terminal region of σ70 in an E. coli two-hybrid assay. Replacement of the C-terminal 17 residues of σ70 with comparable σ38 residues abolishes the interaction with MotANTD in this assay, as does the introduction of the amino acid substitution R608C. Furthermore, in vitro transcription experiments indicate that a polymerase reconstituted with a σ70 that lacks C-terminal amino acids 604 to 613 or 608 to 613 is defective for MotA-dependent activation. We also show that a proteolyzed fragment of MotA that contains the C-terminal half (MotACTD) binds DNA with a K D(app) that is similar to that of full-length MotA. Our results support a model for MotA-dependent activation in which protein-protein contact between DNA-bound MotA and the far-C-terminal region of σ70 helps to substitute functionally for an interaction between σ70 and a promoter −35 element.

Substituted 4-Formyl-2H-chromen-2-ones: Their Reaction with N-(2,3,4,6-Tetra-Oacetyl- β-D-galactopyranosyl)thiosemicarbazide, Antibacterial and Antifungal Activity of Their Thiosemicarbazone Products

2020 ◽  
Vol 24 (19) ◽  
pp. 2272-2282
Author(s):  
Vu Ngoc Toan ◽  
Nguyen Minh Tri ◽  
Nguyen Dinh Thanh
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Selenium Dioxide ◽  
Antibacterial And Antifungal Activity ◽  
E Coli ◽  
Antibacterial And Antifungal Activities ◽  
Alkyl Ethers ◽  
Antibacterial And Antifungal

Several 6- and 7-alkoxy-2-oxo-2H-chromene-4-carbaldehydes were prepared from corresponding alkyl ethers of 6- and 7-hydroxy-4-methyl-2-oxo-2H-chromen-2-ones by oxidation using selenium dioxide. 6- and 7-Alkoxy-4-methyl-2H-chromenes were obtained with yields of 57-85%. Corresponding 4-carbaldehyde derivatives were prepared with yields of 41-67%. Thiosemicarbazones of these aldehydes with D-galactose moiety were synthesized by reaction of these aldehydes with N-(2,3,4,6-tetra-O-acetyl-β-Dgalactopyranosyl) thiosemicarbazide with yields of 62-74%. These thiosemicarbazones were screened for their antibacterial and antifungal activities in vitro against bacteria, such as Staphylococcus aureus, Escherichia coli, and fungi, such as Aspergillus niger, Candida albicans. Several compounds exhibited strong inhibitory activity with MIC values of 0.78- 1.56 μM, including 8a (against S. aureus, E. coli, and C. albicans), 8d (against E. coli and A. niger), 9a (against S. aureus), and 9c (against S. aureus and C. albicans).

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