Heterologous high-level E. coli expression, purification and biophysical characterization of the spine-associated RapGAP (SPAR) PDZ domain

2008 ◽  
Vol 62 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Breann L. Brown ◽  
Michael Hadley ◽  
Rebecca Page
Keyword(s):  
Pdz Domain ◽  
Biophysical Characterization ◽  
E Coli ◽  
High Level

Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt

2017 ◽  
Vol 1861 (11) ◽  
pp. 2702-2709 ◽  
Author(s):  
A. Gilardi ◽  
S.P. Bhamidimarri ◽  
M. Brönstrup ◽  
U. Bilitewski ◽  
R.K.R. Marreddy ◽  
...  
Keyword(s):  
Biophysical Characterization ◽  
E Coli

Cloning and expression of DiT33 from Dirofilaria immitis: a specific and early marker of heartworm infection

Parasitology ◽  
1996 ◽  
Vol 112 (3) ◽  
pp. 331-338 ◽  
Author(s):  
X. Q. Hong ◽  
J. Santiago Mejia ◽  
S. Kumar ◽  
F. B. Perler ◽  
C. K. S. Carlow
Keyword(s):  
Dirofilaria Immitis ◽  
Cloning And Expression ◽  
E Coli ◽  
Spliced Leader ◽  
Isolation And Characterization ◽  
The Family ◽  
Heartworm Infection ◽  
High Level ◽  
Control And Management

SUMMARYDirofilaria immitis is an important filarial parasite of dogs and cats, and a useful model for human filariasis. Current diagnostic tests for heartworm infection in animals rely on the presence of fecund female worms (usually found 6·5 months post-infection or later) and therefore fail to detect pre-patent infections. Putative pepsin inhibitors from 2 filarial parasites of humans namely Onchocerca volvulus (Ov33, Oc3.6, OvDSB) and Brugia malayi (Bm33), have been shown to be useful in diagnosis of onchocerciasis and lymphatic filariasis, respectively. Previous studies have suggested that a homologue exists in D. immitis (DiT33), which may have potential in diagnosis of heartworm infection. In this study, the isolation and characterization of a cDNA clone encoding DiT33 is described.‡ This cDNA contains 12 bases of the nematode-specific 22 nucleotide spliced leader sequence and encodes a 26·4 kDa-protein with a high level of similarity (87–89%) to other filarial members of the family. DJT33 was over-expressed in E. coli as a fusion with the maltose-binding protein and serological analysis was performed using a panel of clinically defined dog sera. The findings of this study indicate that DiT33 is a promising antigen for the early detection of D. immitis and may be a valuable tool in the control and management of heartworm infection.

scholarly journals Molecular characterization of extended-spectrum beta-lactamase producing Enterobacteriaceae in a Saudi Arabian tertiary hospital

2014 ◽  
Vol 8 (03) ◽  
pp. 282-288 ◽  
Author(s):  
Hoda Hassan ◽  
Baha Abdalhamid
Keyword(s):  
Tertiary Hospital ◽  
Multidrug Resistant ◽  
Beta Lactamase ◽  
M Gene ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Vitek 2 ◽  
High Level

Introduction: The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Proteus mirabilis (P. mirabilis). In addition, different methods for detection of these enzymes, including the newly introduced CHROMagar ESBL, were evaluated. Methodology: A total of 382 Enterobacteriaceae clinical isolates were obtained from King Fahad Specialist Hospital – Dammam, during 2011 and screened for production of ESBL using advanced expert system of Vitek 2, CHROMagar and ESBL-E-strips. PCR assay was used to detect blaTEM, blaSHV, and blaCTX-M genes. Susceptibility to a panel of antibiotics was determined. Results: The overall proportion of ESBL-producing enterobacterial isolates was 30.6%, which was higher in E. coli (35.8%) than in K. pneumoniae (25.7%). ESBL genotypes showed remarkable increase in the CTX-M (97.4%) compared to SHV (23.1%). The predominant ESBL was CTX-M- 15 (92.1 %). No TEM ESBL was detected in this study. The Vitek2 showed the highest sensitivity (100%), and the CHROMagar had the lowest specificity (97.3%) compared to the molecular method. All isolates were susceptible to imipenem and meropenem. Conclusions: This study confirms a high level of blaCTX-M positive ESBL isolates are circulating in the Eastern Province of Saudi Arabia. The trend of a multidrug-resistant profile associated with the recovery of the blaCTX-M gene is alarming.

scholarly journals High-level of expression, purification and characterization of active Artin M Lectin in different E. Coli hosts

2009 ◽  
Vol 25 ◽  
pp. S293-S294
Author(s):  
M.C.D.S. Pranchevicius ◽  
L. Oliveira ◽  
N.C. Avanci ◽  
J.C. Rosa ◽  
A.C. Quiapim ◽  
...  
Keyword(s):  
Purification And Characterization ◽  
E Coli ◽  
High Level

scholarly journals Characterization of Dihydrofolate Reductase Genes from Trimethoprim-Susceptible and Trimethoprim-Resistant Strains ofEnterococcus faecalis

1999 ◽  
Vol 43 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Teresa M. Coque ◽  
Kavindra V. Singh ◽  
George M. Weinstock ◽  
Barbara E. Murray
Keyword(s):  
Amino Acids ◽  
Nucleotide Sequence ◽  
E Coli ◽  
Integrative Vector ◽  
Dihydrofolate Reductases ◽  
Multiple Copies ◽  
Gram Negative Organisms ◽  
High Level

Enterococci are usually susceptible in vitro to trimethoprim; however, high-level resistance (HLR) (MICs, >1,024 μg/ml) has been reported. We studied Enterococcus faecalis DEL, for which the trimethoprim MIC was >1,024 μg/ml. No transfer of resistance was achieved by broth or filter matings. Two different genes that conferred trimethoprim resistance when they were cloned in Escherichia coli (MICs, 128 and >1,024 μg/ml) were studied. One gene that coded for a polypeptide of 165 amino acids (MIC, 128 μg/ml forE. coli) was identical to dfr homologs that we cloned from a trimethoprim-susceptible E. faecalis strain, and it is presumed to be the intrinsic E. faecalis dfr gene (which causes resistance in E. coli when cloned in multiple copies); this gene was designated dfrE. The nucleotide sequence 5′ to this dfr gene showed similarity to thymidylate synthetase genes, suggesting that the dfr andthy genes from E. faecalis are located in tandem. The E. faecalis gene that conferred HLR to trimethoprim in E. coli, designated dfrF, codes for a predicted polypeptide of 165 amino acids with 38 to 64% similarity with other dihydrofolate reductases from gram-positive and gram-negative organisms. The nucleotide sequence 5′ to dfrFdid not show similarity to the thy sequences. A DNA probe for dfrF hybridized under high-stringency conditions only to colony lysates of enterococci for which the trimethoprim MIC was >1,024 μg/ml; there was no hybridization to plasmid DNA from the strain of origin. To confirm that this gene causes trimethoprim resistance in enterococci, we cloned it into the integrative vector pAT113 and electroporated it into RH110 (E. faecalisOG1RF::Tn916ΔEm) (trimethoprim MIC, 0.5 μg/ml), which resulted in RH110 derivatives for which the trimethoprim MIC was >1,024 μg/ml. These results indicate thatdfrF is an acquired but probably chromosomally located gene which is responsible for in vitro HLR to trimethoprim in E. faecalis.

scholarly journals Characterization of Solanum melongena Thioesterases Related to Tomato Methylketone Synthase 2

Genes ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 549 ◽  
Author(s):  
Khuat ◽  
Bui ◽  
Tran ◽  
Truong ◽  
Nguyen ◽  
...  
Keyword(s):  
Methyl Salicylate ◽  
Functional Characterization ◽  
Solanum Melongena ◽  
Industrial Applications ◽  
Biofuel Production ◽  
Mechanical Wounding ◽  
Acyl Carrier Proteins ◽  
E Coli ◽  
High Level

2-Methylketones are involved in plant defense and fragrance and have industrial applications as flavor additives and for biofuel production. We isolated three genes from the crop plant Solanum melongena (eggplant) and investigated these as candidates for methylketone production. The wild tomato methylketone synthase 2 (ShMKS2), which hydrolyzes β-ketoacyl-acyl carrier proteins (ACP) to release β-ketoacids in the penultimate step of methylketone synthesis, was used as a query to identify three homologs from S. melongena: SmMKS2-1, SmMKS2-2, and SmMKS2-3. Expression and functional characterization of SmMKS2s in E. coli showed that SmMKS2-1 and SmMKS2-2 exhibited the thioesterase activity against different β-ketoacyl-ACP substrates to generate the corresponding saturated and unsaturated β-ketoacids, which can undergo decarboxylation to form their respective 2-methylketone products, whereas SmMKS2-3 showed no activity. SmMKS2-1 was expressed at high level in leaves, stems, roots, flowers, and fruits, whereas expression of SmMKS2-2 and SmMKS2-3 was mainly in flowers and fruits, respectively. Expression of SmMKS2-1 was induced in leaves by mechanical wounding, and by methyl jasmonate or methyl salicylate, but SmMKS2-2 and SmMKS2-3 genes were not induced. SmMKS2-1 is a candidate for methylketone-based defense in eggplant, and both SmMKS2-1 and SmMKS2-2 are novel MKS2 enzymes for biosynthesis of methylketones as feedstocks to biofuel production.

scholarly journals A qnr-plasmid allows aminoglycosides to induce SOS in Escherichia coli

2021 ◽  
Author(s):  
Anamaria Babosan ◽  
David Skurnik ◽  
Anaëlle Muggeo ◽  
Gerald Pier ◽  
Thomas Jové ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Fluoroquinolone Antibiotics ◽  
Plasmid Genes ◽  
High Level ◽  
Emergence Of Resistance ◽  
Fad Binding

The plasmid-mediated quinolone resistance (PMQR) genes have been shown to promote high level bacterial resistance to fluoroquinolone antibiotics, potentially leading to clinical treatment failures. In Escherichia coli, sub-inhibitory concentrations (sub-MIC) of the widely used fluoroquinolones are known to induce the SOS response. Interestingly, the expression of several PMQR qnr genes is controlled by the SOS master regulator. During the characterization of a small qnrD-plasmid carried in E. coli, we observed that the aminoglycosides become able to induce the SOS response in this species, thus leading to the transcription of qnrD. We found that induction of the SOS response is due to nitric oxide (NO) accumulation in presence of sub-MIC of aminoglycosides. We demonstrated that the NO accumulation is driven by two plasmid genes, ORF3 and ORF4, whose products act at two levels. ORF3 encode a FAD-binding oxidoreductase which helps NO synthesis, while ORF4 code for an FNR-type transcription factor, related to an O2-responsive regulator of hmp expression, able to repress the Hmp-mediated NO detoxification pathway of E. coli. Thus, this discovery, that other major classes of antibiotics may induce the SOS response could have worthwhile implications for antibiotic stewardship efforts in preventing the emergence of resistance.

Genomic characterization of 16S rRNA methyltransferase-producing Escherichia coli isolates from the Parisian area, France

2020 ◽  
Vol 75 (7) ◽  
pp. 1726-1735 ◽  
Author(s):  
François Caméléna ◽  
Florence Morel ◽  
Manel Merimèche ◽  
Jean-Winoc Decousser ◽  
Hervé Jacquier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Genomic Diversity ◽  
Health Concern ◽  
M Gene ◽  
Genetic Environment ◽  
E Coli ◽  
Genomic Characterization ◽  
High Level

Abstract Background The resistance to all aminoglycosides (AGs) conferred by 16S rRNA methyltransferase enzymes (16S-RMTases) is a major public health concern. Objectives To characterize the resistance genotype, its genetic environment and plasmid support, and the phylogenetic relatedness of 16S-RMTase-producing Escherichia coli from France. Methods We screened 137 E. coli isolates resistant to all clinically relevant AGs from nine Parisian hospitals for 16S-RMTases. WGS was performed on clinical isolates with high-level AG resistance (MIC ≥256 mg/L) and their transformants. Results Thirty of the 137 AG-resistant E. coli produced 16S-RMTases: 11 ArmA, 18 RmtB and 1 RmtC. The 16S-RMTase producers were also resistant to third-generation cephalosporins (90% due to a blaCTX-M gene), co-trimoxazole, fluoroquinolones and carbapenems (blaNDM and blaVIM genes) in 97%, 83%, 70% and 10% of cases, respectively. Phylogenomic diversity was high in ArmA producers, with 10 different STs, but a similar genetic environment, with the Tn1548 transposon carried by a plasmid closely related to pCTX-M-3 in 6/11 isolates. Conversely, RmtB producers belonged to 12 STs, the most frequent being ST405 and ST complex (STc) 10 (four and four isolates, respectively). The rmtB gene was carried by IncF plasmids in 10 isolates and was found in different genetic environments. The rmtC gene was carried by the pNDM-US plasmid. Conclusions ArmA and RmtB are the predominant 16S-RMTases in France, but their spread follows two different patterns: (i) dissemination of a conserved genetic support carrying armA in E. coli with high levels of genomic diversity; and (ii) various genetic environments surrounding rmtB in clonally related E. coli.

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