scholarly journals Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes inEscherichia coliduring Selenite Reduction

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Antonia Y. Tetteh ◽  
Katherine H. Sun ◽  
Chiu-Yueh Hung ◽  
Farooqahmed S. Kittur ◽  
Gordon C. Ibeanu ◽  
...  
Keyword(s):  
Growth Response ◽  
Inhibitory Concentration ◽  
Molecular Level ◽  
Transcriptional Response ◽  
Reduction Process ◽  
Elemental Selenium ◽  
Bacterial Cells ◽  
Quantitative Real Time Pcr ◽  
Selenite Reduction ◽  
E Coli

Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We usedEscherichia colistrain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of threeE. coliselenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3treatment inhibited growth by∼50% while 0.001 to 0.01 mM treatments stimulated cell growth by∼30%. Under 50% inhibitory or 30% stimulatory Na2SeO3concentration, selenopolypeptide genes (fdnG,fdoG, andfdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S) metabolic geneiscSand two previously reported selenite-responsive genessodAandgutSwere also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite inE. colivia induction of these genes involved in the selenite reduction process.

scholarly journals Identification of a Dithiazoline Inhibitor of Escherichia colil,d-Carboxypeptidase A

2005 ◽  
Vol 49 (11) ◽  
pp. 4500-4507 ◽  
Author(s):  
Ellen Z. Baum ◽  
Steven M. Crespo-Carbone ◽  
Barbara Foleno ◽  
Sean Peng ◽  
Jamese J. Hilliard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Phase Behavior ◽  
High Throughput Screening ◽  
Deletion Mutant ◽  
Inhibitory Concentration ◽  
Bacterial Cells ◽  
Carboxypeptidase A ◽  
E Coli ◽  
Bacterial Peptidoglycan

ABSTRACT The enzyme l,d-carboxypeptidase A is involved in the recycling of bacterial peptidoglycan and is essential in Escherichia coli during stationary phase. By high-throughput screening, we have identified a dithiazoline inhibitor of the enzyme with a 50% inhibitory concentration of 3 μM. The inhibitor appeared to cause lysis of E. coli during stationary phase, behavior that is similar to a previously described deletion mutant of l,d-carboxypeptidase A (M. F. Templin, A. Ursinus, and J.-V. Holtje, EMBO J. 18:4108-4117, 1999). As much as a one-log drop in CFU in stationary phase was observed upon treatment of E. coli with the inhibitor, and the amount of intracellular tetrapeptide substrate increased by approximately 33%, consistent with inhibition of the enzyme within bacterial cells. Stationary-phase targets such as l,d-carboxypeptidase A are largely underrepresented as targets of the antibiotic armamentarium but provide potential opportunities to interfere with bacterial growth and persistence.

scholarly journals Development of Resistance in Escherichia coli ATCC25922 under Exposure of Sub-Inhibitory Concentration of Olaquindox

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 791
Author(s):  
Yufeng Gu ◽  
Shuge Wang ◽  
Lulu Huang ◽  
Wei Sa ◽  
Jun Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Bacterial Resistance ◽  
Inhibitory Concentration ◽  
Tricarboxylic Acid Cycle ◽  
Resistance Mechanism ◽  
Reduction Process ◽  
E Coli ◽  
Development Of Resistance ◽  
Oxidation Reduction

Quinoxaline1,4-di-N-oxides (QdNOs) are a class of important antibacterial drugs of veterinary use, of which the drug resistance mechanism has not yet been clearly explained. This study investigated the molecular mechanism of development of resistance in Escherichia coli (E. coli) under the pressure of sub-inhibitory concentration (sub-MIC) of olaquindox (OLA), a representative QdNOs drug. In vitro challenge of E. coli with 1/100× MIC to 1/2× MIC of OLA showed that the bacteria needed a longer time to develop resistance and could only achieve low to moderate levels of resistance as well as form weak biofilms. The transcriptomic and genomic profiles of the resistant E. coli induced by sub-MIC of OLA demonstrated that genes involved in tricarboxylic acid cycle, oxidation-reduction process, biofilm formation, and efflux pumps were up-regulated, while genes involved in DNA repair and outer membrane porin were down-regulated. Mutation rates were significantly increased in the sub-MIC OLA-treated bacteria and the mutated genes were mainly involved in the oxidation-reduction process, DNA repair, and replication. The SNPs were found in degQ, ks71A, vgrG, bigA, cusA, and DR76-4702 genes, which were covered in both transcriptomic and genomic profiles. This study provides new insights into the resistance mechanism of QdNOs and increases the current data pertaining to the development of bacterial resistance under the stress of antibacterials at sub-MIC concentrations.

scholarly journals Antimicrobial activity of Lippia sidoides Cham. (Verbenaceae) essential oil against Staphylococcus aureus and Escherichia coli

2011 ◽  
Vol 13 (3) ◽  
pp. 293-297 ◽  
Author(s):  
C.E Castro ◽  
J.M Ribeiro ◽  
T.T Diniz ◽  
A.C Almeida ◽  
L.C Ferreira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Essential Oil ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Antibacterial Effect ◽  
Bactericidal Effect ◽  
Bacterial Cells ◽  
E Coli ◽  
Lippia Sidoides

The antibacterial effect of Lippia sidoides (rosemary pepper) essential oil was tested against the bacteria Staphylococcus aureus and Escherichia coli isolated from homemade Minas cheese produced in Brazil. The Minimum Inhibitory Concentration (MIC) determined in the Dilution Test was 13 µL oil mL-1 for both bacteria, which characterizes inhibitory action in broth for a 24-hour interaction period. The Minimum Bactericidal Concentration (MBC) determined in the Suspension Test, with one minute of contact, was 25 µL oil mL-1 for both tested bacteria, obtaining at this concentration a bactericidal effect of 99.9% on the viable bacterial cells from each sample. Results demonstrated the bacterial activity of Lippia sidoides essential oil against S. aureus and E. coli, suggesting its use as an antibacterial agent in foods.

Increased Transcription of the Phosphate-Specific Transport System of Escherichia coli O157:H7 after Exposure to Sodium Benzoate

2010 ◽  
Vol 73 (5) ◽  
pp. 819-824 ◽  
Author(s):  
FAITH J. CRITZER ◽  
DORIS H. D'SOUZA ◽  
ARNOLD M. SAXTON ◽  
DAVID A. GOLDEN
Keyword(s):  
Escherichia Coli ◽  
Sodium Benzoate ◽  
Efflux Pump ◽  
Transcriptional Response ◽  
Luria Bertani ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
E Coli ◽  
Specific Transport ◽  
Pst System

Sodium benzoate is a widely used food antimicrobial in drinks and fruit juices. A microarray study was conducted to determine the transcriptional response of Escherichia coli O157:H7 to 0.5% (wt/vol) sodium benzoate. E. coli O157:H7 grown in 150 ml of Luria-Bertani broth was exposed to 0% (control) and 0.5% sodium benzoate. Each treatment was duplicated and sampled at 0 (immediately after exposure), 5, 15, 30, and 60 min. Total RNA was extracted and analyzed with E. coli 2.0 Gene Chips. Significant ontology categories affected by sodium benzoate exposure were determined with JProGO software. The phosphate-specific transport (Pst) system transports inorganic phosphate into bacterial cells, under phosphate-limited conditions. The Pst system was found to be highly upregulated. Increased expression of the Pst system was observed after the short 5 min of exposure to sodium benzoate; pstS, pstA, pstB, and pstC genes were upregulated more than twofold (linear scale) at 5, 15, 30, and 60 min. Increased expression of several other efflux systems, such as AcrAB-TolC, was also observed. The Pst system may act as an efflux pump under these stress-adapted conditions, as well as increase transport of phosphorus to aid in DNA, RNA, ATP, and phospholipid production. Understanding adaptations of Escherichia coli O157:H7 under antimicrobial exposure is essential to better understand and implement methods to inhibit or control its survival in foods.

scholarly journals The Hek Outer Membrane Protein of Escherichia coli Strain RS218 Binds to Proteoglycan and Utilizes a Single Extracellular Loop for Adherence, Invasion, and Autoaggregation

2007 ◽  
Vol 76 (3) ◽  
pp. 1135-1142 ◽  
Author(s):  
Robert P. Fagan ◽  
Matthew A. Lambert ◽  
Stephen G. J. Smith
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Epithelial Cells ◽  
Membrane Protein ◽  
Molecular Level ◽  
Coli Strain ◽  
Bacterial Cells ◽  
Extracellular Loop ◽  
Gram Negative ◽  
E Coli

ABSTRACT Escherichia coli is the principal gram-negative causative agent of sepsis and meningitis in neonates. The pathogenesis of meningitis due to E. coli K1 involves mucosal colonization, transcytosis of epithelial cells, survival in the bloodstream, and eventually invasion of the meninges. The last two aspects have been well characterized at a molecular level. Less is known about the early stages of pathogenesis, i.e., adhesion to and invasion of epithelial cells. We have previously reported that the Hek protein causes autoaggregation and can mediate adherence to and invasion of epithelial cells. Here, we report that Hek-mediated adherence is dependent on binding to glycosoaminoglycan, in particular, heparin. The ability to hemagglutinate, autoaggregate, adhere, and invade is contingent on a putative 25-amino-acid loop that is exposed to the outside of the bacterial cells.

scholarly journals Untargeted Metabolomics Investigation on Selenite Reduction to Elemental Selenium by Bacillus mycoides SeITE01

2021 ◽  
Vol 12 ◽  
Author(s):  
Greta Baggio ◽  
Ryan A. Groves ◽  
Roberto Chignola ◽  
Elena Piacenza ◽  
Alessandro Presentato ◽  
...  
Keyword(s):  
Time Course ◽  
Membrane Lipids ◽  
Untargeted Metabolomics ◽  
Elemental Selenium ◽  
Growth Stages ◽  
Bacterial Cells ◽  
Bacillus Mycoides ◽  
Thiol Compounds ◽  
Selenite Reduction ◽  
Signaling Strategies

Bacillus mycoides SeITE01 is an environmental isolate that transforms the oxyanion selenite (SeO32−) into the less bioavailable elemental selenium (Se0) forming biogenic selenium nanoparticles (Bio-SeNPs). In the present study, the reduction of sodium selenite (Na2SeO3) by SeITE01 strain and the effect of SeO32− exposure on the bacterial cells was examined through untargeted metabolomics. A time-course approach was used to monitor both cell pellet and cell free spent medium (referred as intracellular and extracellular, respectively) metabolites in SeITE01 cells treated or not with SeO32−. The results show substantial biochemical changes in SeITE01 cells when exposed to SeO32−. The initial uptake of SeO32− by SeITE01 cells (3h after inoculation) shows both an increase in intracellular levels of 4-hydroxybenzoate and indole-3-acetic acid, and an extracellular accumulation of guanosine, which are metabolites involved in general stress response adapting strategies. Proactive and defensive mechanisms against SeO32− are observed between the end of lag (12h) and beginning of exponential (18h) phases. Glutathione and N-acetyl-L-cysteine are thiol compounds that would be mainly involved in Painter-type reaction for the reduction and detoxification of SeO32− to Se0. In these growth stages, thiol metabolites perform a dual role, both acting against the toxic and harmful presence of the oxyanion and as substrate or reducing sources to scavenge ROS production. Moreover, detection of the amino acids L-threonine and ornithine suggests changes in membrane lipids. Starting from stationary phase (24 and 48h), metabolites related to the formation and release of SeNPs in the extracellular environment begin to be observed. 5-hydroxyindole acetate, D-[+]-glucosamine, 4-methyl-2-oxo pentanoic acid, and ethanolamine phosphate may represent signaling strategies following SeNPs release from the cytoplasmic compartment, with consequent damage to SeITE01 cell membranes. This is also accompanied by intracellular accumulation of trans-4-hydroxyproline and L-proline, which likely represent osmoprotectant activity. The identification of these metabolites suggests the activation of signaling strategies that would protect the bacterial cells from SeO32− toxicity while it is converting into SeNPs.

scholarly journals Antibacterial characteristics of orange pigment extracted from Monascus pigments against Escherichia coli

2016 ◽  
Vol 34 (No. 3) ◽  
pp. 197-203 ◽  
Author(s):  
Zhao Guo-Ping ◽  
Li Ying-Qiu ◽  
Yang Jie ◽  
Cui Kai-Yu
Keyword(s):  
Escherichia Coli ◽  
Inhibitory Concentration ◽  
Cytoplasmic Membrane ◽  
Inhibition Zone ◽  
Bacterial Membrane ◽  
Bacterial Cells ◽  
Orange Pigment ◽  
E Coli ◽  
Monascus Pigments ◽  
Egg Pc

The antibacterial characteristics of orange pigment, which is one of the Monascus pigments, against Escherichia coli were investigated. Orange pigment exhibited strong antibacterial activity against E. coli evidenced by an increase in the diameter of inhibition zone with orange pigment treatment. The concentration of 2.5 mg/ml was the minimum inhibitory concentration of orange pigment against E. coli. Scanning electron microscopy revealed that orange pigment could damage bacterial cells, eventually resulting in cell death. The increase in the electric conductivity of bacterial cell suspensions suggested that the cytoplasmic membrane was broken by treatment with orange pigment. The result of orange pigment incorporation into egg PC further demonstrated the interaction between orange pigment and the phospholipid led to the disruption of bacterial membrane.

Effect of piperacillin on morphology and viability of gram-negative bacteria

1984 ◽  
Vol 42 ◽  
pp. 218-219
Author(s):  
R. H. Liss
Keyword(s):  
Inhibitory Concentration ◽  
Cytoplasmic Membrane ◽  
Drug Binding ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Drug Induced ◽  
Penicillin Binding Proteins ◽  
Lactam Antibiotic ◽  
Drug Free ◽  
Tube Dilution

Piperacillip (PIP) is b-[D(-)-α-(4-ethy1-2,3-dioxo-l-piperzinylcar-bonylamino)-α-phenylacetamido]-penicillanate. The broad spectrum semisynthetic β-lactam antibiotic is believed to effect bactericidal activity through its affinity for penicillin-binding proteins (PBPs), enzymes on the bacterial cytoplasmic membrane that control elongation and septation during cell growth and division. The purpose of this study was to correlate penetration and binding of 14C-PIP in bacterial cells with drug-induced lethal changes assessed by microscopic, microbiologic and biochemical methods.The bacteria used were clinical isolates of Escherichia coli and Pseudomonas aeruginosa (Figure 1). Sensitivity to the drug was determined by serial tube dilution in Trypticase Soy Broth (BBL) at an inoculum of 104 organisms/ml; the minimum inhibitory concentration of piperacillin for both bacteria was 1 μg/ml. To assess drug binding to PBPs, the bacteria were incubated with 14C-PIP (5 μg/0.09 μCi/ml); controls, in drug-free medium.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Toxic Effect of 2-ethyl (bicyclo[2.2.1] heptane) on Bacterial Cells

2019 ◽  
Vol 35 (6) ◽  
pp. 67-72 ◽  
Author(s):  
I.V. Manukhov ◽  
L.S. Yaguzhinsky ◽  
M.V. Bermeshev ◽  
M.A. Zisman ◽  
V.G. Pevgov ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Atmospheric Oxygen ◽  
Inducible Promoter ◽  
Oxygen Species ◽  
Bacterial Cells ◽  
Unique Identifier ◽  
E Coli ◽  
Lux Biosensors ◽  
High Level ◽  
Ministry Of Higher Education

Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).

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