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

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.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.11.4500-4507.2005 ◽

2005 ◽

Vol 49 (11) ◽

pp. 4500-4507 ◽

Cited By ~ 10

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.

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

Revista Brasileira de Plantas Medicinais ◽

10.1590/s1516-05722011000300007 ◽

2011 ◽

Vol 13 (3) ◽

pp. 293-297 ◽

Cited By ~ 6

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111203 ◽

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.

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Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

BMC Microbiology ◽

10.1186/s12866-021-02097-2 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Abdulkader Masri ◽

Naveed Ahmed Khan ◽

Muhammad Zarul Hanifah Md Zoqratt ◽

Qasim Ayub ◽

Ayaz Anwar ◽

...

Keyword(s):

Escherichia Coli ◽

Silver Nanoparticles ◽

Minimum Inhibitory Concentration ◽

Inhibitory Concentration ◽

Neonatal Meningitis ◽

E Coli ◽

Drug Candidates ◽

Metabolic Genes ◽

Genetic Mechanisms ◽

Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

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Toxicity of the First Ten MEIC Chemicals to Bacteria

Alternatives to Laboratory Animals ◽

10.1177/026119299302100205 ◽

1993 ◽

Vol 21 (2) ◽

pp. 151-155

Author(s):

Gustaw Kerszman

Keyword(s):

Escherichia Coli ◽

Bacillus Subtilis ◽

Linear Regression ◽

Minimal Inhibitory Concentration ◽

Blood Concentration ◽

Inhibitory Concentration ◽

Human Lymphocytes ◽

Bacterial Species ◽

E Coli ◽

Mild Toxicity

The toxicity of the first ten MEIC chemicals to Escherichia coli and Bacillus subtilis was examined. Nine of the chemicals were toxic to the bacteria, with the minimal inhibitory concentration (MIC) ranging from 10-3 to 4.4M. The sensitivities of both organisms were similar, but the effect on E. coli was often bactericidal, while it was bacteriostatic for B. subtilis. Digoxin was not detectably toxic to either bacterial species. Amitriptyline and FeSO4 were relatively less toxic to the bacteria than to human cells. For seven chemicals, a highly significant linear regression was established between log MIC in bacteria and log of blood concentration, giving lethal and moderate/mild toxicity in humans, as well as with toxicity to human lymphocytes.

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Interaction of Gram-Negative Bacteria with the Lysosomal Fraction of Polymorphonuclear Leukocytes II. Changes in the Cell Envelope of Escherichia coli

Infection and Immunity ◽

10.1128/iai.1.3.311-318.1970 ◽

1970 ◽

Vol 1 (3) ◽

pp. 311-318

Author(s):

D. Friedberg ◽

I. Friedberg ◽

M. Shilo

Keyword(s):

Escherichia Coli ◽

Polymorphonuclear Leukocytes ◽

Cytoplasmic Membrane ◽

Morphological Changes ◽

Cell Envelope ◽

Gram Negative Bacteria ◽

Intact Cells ◽

Lysosomal Fraction ◽

E Coli ◽

Absorbing Material

Interaction of lysosomal fraction with Escherichia coli caused damage to the cell envelope of these intact cells and to the cytoplasmic membrane of E. coli spheroplasts. The damage to the cytoplasmic membrane was manifested in the release of 260-nm absorbing material and β-galactosidase from the spheroplasts, and by increased permeability of cryptic cells to O -nitrophenyl-β- d -galactopyranoside; damage to the cell wall was measured by release of alkaline phosphatase. Microscope observation showed morphological changes in the cell envelope.

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One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

Cold Spring Harbor Protocols ◽

10.1101/pdb.prot101212 ◽

2021 ◽

Vol 2021 (11) ◽

pp. pdb.prot101212 ◽

Cited By ~ 1

Author(s):

Michael R. Green ◽

Joseph Sambrook

Keyword(s):

Escherichia Coli ◽

Convenient Method ◽

Plasmid Dna ◽

Transformation Efficiency ◽

Bacterial Cells ◽

E Coli ◽

One Step ◽

And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

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

Microbiology ◽

10.1099/mic.0.001031 ◽

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.

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Bacterial Secretions of Nonpathogenic Escherichia coli Elicit Inflammatory Pathways: a Closer Investigation of Interkingdom Signaling

mBio ◽

10.1128/mbio.00025-15 ◽

2015 ◽

Vol 6 (2) ◽

Cited By ~ 33

Author(s):

Amin Zargar ◽

David N. Quan ◽

Karen K. Carter ◽

Min Guo ◽

Herman O. Sintim ◽

...

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Negative Feedback ◽

Cell Contact ◽

Bacterial Cells ◽

Content Type ◽

Phenotypic Differences ◽

E Coli ◽

Autoinducer 2 ◽

Human Epithelial Cells

ABSTRACTThere have been many studies on the relationship between nonpathogenic bacteria and human epithelial cells; however, the bidirectional effects of the secretomes (secreted substances in which there is no direct bacterium-cell contact) have yet to be fully investigated. In this study, we use a transwell model to explore the transcriptomic effects of bacterial secretions from two different nonpathogenicEscherichia colistrains on the human colonic cell line HCT-8 using next-generation transcriptome sequencing (RNA-Seq).E. coliBL21 and W3110, while genetically very similar (99.1% homology), exhibit key phenotypic differences, including differences in their production of macromolecular structures (e.g., flagella and lipopolysaccharide) and in their secretion of metabolic byproducts (e.g., acetate) and signaling molecules (e.g., quorum-sensing autoinducer 2 [AI-2]). After analysis of differential epithelial responses to the respective secretomes, this study shows for the first time that a nonpathogenic bacterial secretome activates the NF-κB-mediated cytokine-cytokine receptor pathways while also upregulating negative-feedback components, including the NOD-like signaling pathway. Because of AI-2's relevance as a bacterium-bacterium signaling molecule and the differences in its secretion rates between these strains, we investigated its role in HCT-8 cells. We found that the expression of the inflammatory cytokine interleukin 8 (IL-8) responded to AI-2 with a pattern of rapid upregulation before subsequent downregulation after 24 h. Collectively, these data demonstrate that secreted products from nonpathogenic bacteria stimulate the transcription of immune-related biological pathways, followed by the upregulation of negative-feedback elements that may serve to temper the inflammatory response.IMPORTANCEThe symbiotic relationship between the microbiome and the host is important in the maintenance of human health. There is a growing need to further understand the nature of these relationships to aid in the development of homeostatic probiotics and also in the design of novel antimicrobial therapeutics. To our knowledge, this is the first global-transcriptome study of bacteria cocultured with human epithelial cells in a model to determine the transcriptional effects of epithelial cells in which epithelial and bacterial cells are allowed to “communicate” with each other only through diffusible small molecules and proteins. By beginning to demarcate the direct and indirect effects of bacteria on the gastrointestinal (GI) tract, two-way interkingdom communication can potentially be mediated between host and microbe.

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Synergism of the Combination of Traditional Antibiotics and Novel Phenolic Compounds against Escherichia coli

Pathogens ◽

10.3390/pathogens9100811 ◽

2020 ◽

Vol 9 (10) ◽

pp. 811

Author(s):

Md. Akil Hossain ◽

Hae-Chul Park ◽

Sung-Won Park ◽

Seung-Chun Park ◽

Min-Goo Seo ◽

...

Keyword(s):

Escherichia Coli ◽

Rattus Norvegicus ◽

Inhibitory Concentration ◽

Epicatechin Gallate ◽

Antibiotic Resistant ◽

E Coli ◽

Pathogenic Escherichia Coli ◽

Resistant Strains ◽

Novel Approaches ◽

Rapid Emergence

Pathogenic Escherichia coli (E. coli)-associated infections are becoming difficult to treat because of the rapid emergence of antibiotic-resistant strains. Novel approaches are required to prevent the progression of resistance and to extend the lifespan of existing antibiotics. This study was designed to improve the effectiveness of traditional antibiotics against E. coli using a combination of the gallic acid (GA), hamamelitannin, epicatechin gallate, epigallocatechin, and epicatechin. The fractional inhibitory concentration index (FICI) of each of the phenolic compound-antibiotic combinations against E. coli was ascertained. Considering the clinical significance and FICI, two combinations (hamamelitannin-erythromycin and GA-ampicillin) were evaluated for their impact on certain virulence factors of E. coli. Finally, the effects of hamamelitannin and GA on Rattus norvegicus (IEC-6) cell viability were investigated. The FICIs of the antibacterial combinations against E. coli were 0.281–1.008. The GA-ampicillin and hamamelitannin-erythromycin combinations more effectively prohibited the growth, biofilm viability, and swim and swarm motilities of E. coli than individual antibiotics. The concentration of hamamelitannin and GA required to reduce viability by 50% (IC50) in IEC-6 cells was 988.54 μM and 564.55 μM, correspondingly. GA-ampicillin and hamamelitannin-erythromycin may be potent combinations and promising candidates for eradicating pathogenic E. coli in humans and animals.

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