scholarly journals Lux-biosensors: screening biologically active compounds for genotoxicity

2016 ◽  
Vol 14 (4) ◽  
pp. 52 ◽  
Author(s):  
Elena V Igonina ◽  
Mariya V Marsova ◽  
Serikbai K Abilev
Keyword(s):  
Oxidative Stress ◽  
Mutagenic Activity ◽  
Sos Response ◽  
Biologically Active ◽  
Published Data ◽  
E Coli ◽  
Lux Operon ◽  
Lux Biosensors ◽  
Catalase Peroxidase ◽  
Pharmacologically Active

To study the ability of metal salts and pharmacologically active drugs to induce the oxidative stress and SOS response in bacteria, a set of lux-biosensors was used. The sensors were based on three E. coli strains carrying recombinant plasmids with lux-operon fused to the promoters of SoxS (superoxide dismutase), KatG (catalase-peroxidase) and ColD (colicin D) genes. The created biosensors were used to analyze the activity of 47 substances, with 16 of them identified to induce SOS-response and 6 - to induce oxidative stress. The results observed were compared to the previously published data on the mutagenic activity of the same 47 substances evaluated using Ames test. The comparison had shown full coincidence for 42 from 47 substances analyzed. We discuss the possibility to use the lux-based biosensors for the screening of the genetic activity of chemical compounds.

Lux-biosensors for detection of SOS-response, heat shock, and oxidative stress

2010 ◽  
Vol 46 (8) ◽  
pp. 781-788 ◽  
Author(s):  
V. Yu. Kotova ◽  
I. V. Manukhov ◽  
G. B. Zavilgelskii
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Sos Response ◽  
Lux Biosensors ◽  
And Oxidative Stress

Contribution of SOS Genes to H2O2-induced Apoptosis-like Death in Escherichia Coli

2021 ◽  
Author(s):  
Heesu Kim ◽  
Dong Gun Lee
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Treatment Strategies ◽  
Sos Response ◽  
Bacterial Dna ◽  
E Coli ◽  
New Treatment ◽  
Induced Apoptosis ◽  
And Function ◽  
The Relationship

Abstract Hydrogen peroxide (H2O2) is a debriding agent that damages the microbial structure and function by generating various reactive oxygen species (ROS). H2O2-produced hydroxyl radical (OH∙) also exert oxidative stress on microorganisms. The spread of antibiotic resistance in bacteria is a serious issue worldwide, and greater efforts are needed to identify and characterize novel antibacterial mechanisms to develop new treatment strategies. Therefore, this study aimed to clarify the relationship between H2O2 and Escherichia coli and to elucidate a novel antibacterial mechanism(s) of H2O2. Following H2O2 exposure, increased levels of 8-hydroxyldeoxyguanosine and malondialdehyde indicated that H2O2 accelerates oxidation of bacterial DNA and lipids in E. coli. As oxidative damage worsened, the SOS response was triggered. Cell division arrest and resulting filamentation were identified in cells, indicating that LexA was involved in DNA replication. It was also verified that RecA, a representative SOS gene, helps self-cleavage of LexA and acts as a bacterial caspase-like protein. Our findings also showed that dinF is essential to preserve E. coli from H2O2-induced ROS, and furthermore, demonstrated that H2O2-induced SOS response and SOS genes participate differently in guarding E. coli from oxidative stress. As an extreme SOS response is considered apoptosis-like death (ALD) in bacteria, additional experiments were performed to examine the characteristics of ALD. DNA fragmentation and membrane depolarization appeared in H2O2-treated cells, suggesting that H2O2 causes ALD in E. coli. In conclusion, our investigations revealed that ALD is a novel antibacterial mode of action(s) of H2O2 with important contributions from SOS genes.

scholarly journals Constructing of Bacillus subtilis-Based Lux-Biosensors with the Use of Stress-Inducible Promoters

2021 ◽  
Vol 22 (17) ◽  
pp. 9571
Author(s):  
Andrew G. Kessenikh ◽  
Uliana S. Novoyatlova ◽  
Sergey V. Bazhenov ◽  
Eugeniya A. Stepanova ◽  
Svetlana A. Khrulnova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Bacillus Subtilis ◽  
Specific Response ◽  
Mechanisms Of Toxicity ◽  
Inducible Promoters ◽  
E Coli ◽  
Lux Biosensors ◽  
Increased Sensitivity ◽  
Lux Biosensor ◽  
Stress Promoter

Here, we present a new lux-biosensor based on Bacillus subtilis for detecting of DNA-tropic and oxidative stress-causing agents. Hybrid plasmids pNK-DinC, pNK-AlkA, and pNK-MrgA have been constructed, in which the Photorhabdus luminescens reporter genes luxABCDE are transcribed from the stress-inducible promoters of B. subtilis: the SOS promoter PdinC, the methylation-specific response promoter PalkA, and the oxidative stress promoter PmrgA. The luminescence of B. subtilis-based biosensors specifically increases in response to the appearance in the environment of such common toxicants as mitomycin C, methyl methanesulfonate, and H2O2. Comparison with Escherichia coli-based lux-biosensors, where the promoters PdinI, PalkA, and Pdps were used, showed generally similar characteristics. However, for B. subtilis PdinC, a higher response amplitude was observed, and for B. subtilis PalkA, on the contrary, both the amplitude and the range of detectable toxicant concentrations were decreased. B. subtilis PdinC and B. subtilis PmrgA showed increased sensitivity to the genotoxic effects of the 2,2′-bis(bicyclo [2.2.1] heptane) compound, which is a promising propellant, compared to E. coli-based lux-biosensors. The obtained biosensors are applicable for detection of toxicants introduced into soil. Such bacillary biosensors can be used to study the differences in the mechanisms of toxicity against Gram-positive and Gram-negative bacteria.

Redox-mediated interactions of VHb (Vitreoscilla haemoglobin) with OxyR: novel regulation of VHb biosynthesis under oxidative stress

2010 ◽  
Vol 426 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Arvind Anand ◽  
Brian T. Duk ◽  
Sandeep Singh ◽  
Meltem Y. Akbas ◽  
Dale A. Webster ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcriptional Control ◽  
High Sensitivity ◽  
Reduced Form ◽  
Gene Encoding ◽  
Antioxidant Genes ◽  
E Coli ◽  
Hypoxic Conditions ◽  
Catalase Peroxidase

The bacterial haemoglobin from Vitreoscilla, VHb, displays several unusual properties that are unique among the globin family. When the gene encoding VHb, vgb, is expressed from its natural promoter in either Vitreoscilla or Escherichia coli, the level of VHb increases more than 50-fold under hypoxic conditions and decreases significantly during oxidative stress, suggesting similar functioning of the vgb promoter in both organisms. In the present study we show that expression of VHb in E. coli induced the antioxidant genes katG (catalase–peroxidase G) and sodA (superoxide dismutase A) and conferred significant protection from oxidative stress. In contrast, when vgb was expressed in an oxyR mutant of E. coli, VHb levels increased and the strain showed high sensitivity to oxidative stress without induction of antioxidant genes; this indicates the involvement of the oxidative stress regulator OxyR in mediating the protective effect of VHb under oxidative stress. A putative OxyR-binding site was identified within the vgb promoter and a gel-shift assay confirmed its interaction with oxidized OxyR, an interaction which was disrupted by the reduced form of the transcriptional activator Fnr (fumurate and nitrate reductase). This suggested that the redox state of OxyR and Fnr modulates their interaction with the vgb promoter. VHb associated with reduced OxyR in two-hybrid screen experiments and in vitro, converting it into an oxidized state in the presence of NADH, a condition where VHb is known to generate H2O2. These observations unveil a novel mechanism by which VHb may transmit signals to OxyR to autoregulate its own biosynthesis, simultaneously activating oxidative stress functions. The activation of OxyR via VHb, reported in the present paper for the first time, suggests the involvement of VHb in transcriptional control of many other genes as well.

An Efficient Protocol for the Synthesis, Biological Screening and Molecular Docking Studies of 3,4-Dihydropyrimidine-2-one/thione Derivatives

2020 ◽  
Vol 17 (3) ◽  
pp. 330-340
Author(s):  
Ehsan Ullah Mughal ◽  
Hafiz Umar Farooq ◽  
Amina Sadiq ◽  
Hummera Rafique ◽  
Sajjad Hussain Sumrra ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Antifungal Activity ◽  
Docking Studies ◽  
Biologically Active ◽  
Basic Part ◽  
Molecular Docking Studies ◽  
E Coli ◽  
Solvent Free Conditions ◽  
Pharmacologically Active ◽  
Derivatives Of

Introduction: Heterocyclic compounds are vital to life, since they constitute the most interesting part of the pharmacologically active drugs. Dihydropyrimidine-2-one/thione (DHPM) as the heterocyclic nucleus is the basic part of the most natural as well as synthetic drugs. Synthesis of new derivatives of DHPM and screening their pharmacological potential appear to be an important goal. Methodology: In this study, we have synthesized 15 derivatives of 3,4-dihydropyrimidin-2(1H)- ones/thiones through simple one-step synthetic method comprising one-pot condensation of variously substituted benzaldehydes, urea/thiourea and ethyl acetoacetate using ammonium chloride in methanol as well as under solvent-free conditions. In comparison, the former methodology was proved more efficient, convenient and gave higher yields. Moreover, those compounds were screened for their potential against bacterial strains (S. aureus and E. coli) and fungal strains (C. albicans and C. parapsilosis). Results and Discussion: The experimental results revealed that the synthesized compounds are more active against C. albicans fungus as compared to other tested microbes. Amongst all the synthesized derivatives, compound 3 showed significant non-competitive potential antifungal activity in vitro antimicrobial assay. Theoretically, molecular docking studies showed that these compounds can bind effectively to oxidoreductase enzyme of E. coli and CYP-51 oxidoreductase of C. albicans. Conclusion: Herein, we report improved and high yield reaction conditions for the synthesis of biologically active dihydropyrimidine-2-one, and-thione derivatives. Remarkably, most of the synthesized compounds demonstrated moderate to very good antifungal activity in comparison to the antibacterial activity.

scholarly journals Cinnamon Oil Inhibits Shiga Toxin Type 2 Phage Induction and Shiga Toxin Type 2 Production in Escherichia coli O157:H7

2016 ◽  
Vol 82 (22) ◽  
pp. 6531-6540 ◽  
Author(s):  
Lina Sheng ◽  
Barbara Rasco ◽  
Mei-Jun Zhu
Keyword(s):  
Oxidative Stress ◽  
Shiga Toxin ◽  
Sos Response ◽  
Inhibitory Effect ◽  
Cinnamon Oil ◽  
Content Type ◽  
E Coli ◽  
Shiga Toxin 2 ◽  
Rna Polyadenylation

ABSTRACTThis study evaluated the inhibitory effect of cinnamon oil againstEscherichia coliO157:H7 Shiga toxin (Stx) production and further explored the underlying mechanisms. The MIC and minimum bactericidal concentration (MBC) of cinnamon oil againstE. coliO157:H7 were 0.025% and 0.05% (vol/vol), respectively. Cinnamon oil significantly reduced Stx2 production and thestx2mRNA expression that is associated with diminished Vero cell cytotoxicity. Consistently, induction of the Stx-converting phage where thestx2gene is located, along with the total number of phages, decreased proportionally to cinnamon oil concentration. In line with decreased Stx2 phage induction, cinnamon oil at 0.75× and 1.0× MIC eliminated RecA, a key mediator of SOS response, polynucleotide phosphorylase (PNPase), and poly(A) polymerase (PAP I), which positively regulate Stx-converting phages, contributing to reduced Stx-converting phage induction and Stx production. Furthermore, cinnamon oil at 0.75× and 1.0× MIC strongly inhibited theqseBCandluxSexpression associated with decreased AI-2 production, a universal quorum sensing signaling molecule. However, the expression of oxidative stress response genesoxyR,soxR, andrpoSwas increased in response to cinnamon oil at 0.25× or 0.5× MIC, which may contribute to stunted bacterial growth and reduced Stx2 phage induction and Stx2 production due to the inhibitory effect of OxyR on prophage activation. Collectively, cinnamon oil inhibits Stx2 production and Stx2 phage induction inE. coliO157:H7 in multiple ways.IMPORTANCEThis study reports the inhibitory effect of cinnamon oil on Shiga toxin 2 phage induction and Shiga toxin 2 production. Subinhibitory concentrations (concentrations below the MIC) of cinnamon oil reduced Stx2 production,stx2mRNA expression, and cytotoxicity on Vero cells. Subinhibitory concentrations of cinnamon oil also dramatically reduced both the Stx2 phage and total phage induction inE. coliO157:H7, which may be due to the suppression of RNA polyadenylation enzyme PNPase at 0.25× to 1.0× MIC and the downregulation of bacterial SOS response key regulator RecA and RNA polyadenylation enzyme PAP I at 0.75× or 1.0× MIC. Cinnamon oil at higher levels (0.75× and 1.0× MIC) eliminated quorum sensing and oxidative stress. Therefore, cinnamon oil has potential applications as a therapeutic to controlE. coliO157:H7 infection through inhibition of bacterial growth and virulence factors.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

Biologically Active 2,5-Disubstituted-1,3,4-Oxadiazoles

2009 ◽  
Vol 2 (1) ◽  
pp. 390-406
Author(s):  
Harish Rajak ◽  
Murli Dhar Kharya ◽  
Pradeep Mishra
Keyword(s):  
Heterocyclic Compounds ◽  
Medical Literature ◽  
Biological Activities ◽  
Biologically Active ◽  
Pharmacological Properties ◽  
Clinical Use ◽  
Synthetic Drugs ◽  
Physiologic Activity ◽  
Pharmacologically Active

There are vast numbers of pharmacologically active heterocyclic compounds in regular clinical use. The presence of heterocyclic structures in diverse types of compounds is strongly indicative of the profound effects such structure exerts on physiologic activity, and recognition of this is abundantly reflected in efforts to find useful synthetic drugs. The 1,3,4-oxadiazole nucleus has emerged as one of the potential pharmacophore responsible for diverse pharmacological properties. Medical Literature is flooded with reports of a variety of biological activities of 2,5-Disubstituted-1,3,4-oxadiazoles. The present work is an attempt to summarize and enlist the various reports published on biologically active 2,5-disubstituted-1,3,4-oxadiazoles.

Properties and Biotechnological Application of mutant Derivatives of Mini-intein PRP8 from Penicillium chrysogenum with Improved Control of C-terminal Processing

2019 ◽  
Vol 35 (6) ◽  
pp. 91-101
Author(s):  
F.A. Klebanov ◽  
S.E. Cheperegin ◽  
D.G. Kozlov
Keyword(s):  
Penicillium Chrysogenum ◽  
Protein Denaturation ◽  
Biologically Active ◽  
Cultivation Temperature ◽  
Target Proteins ◽  
E Coli ◽  
Complete Inactivation ◽  
Target Molecules ◽  
Proteins And Peptides

Mutant variants of mini-intein PRP8 from Penicillium chrysogenum (Int4b) with improved control of C-terminal processing were characterized. The presented variants can serve as a basis for self-removed polypeptide tags capable of carrying an affine label and allowing to optimize the process of obtaining target proteins and peptides in E. coli cells. They allow to synthesize target molecules in the composition of soluble and insoluble hybrid proteins (fusions), provide their afnne purification, autocatalytic processing and obtaining mature target products. The presented variants have a number of features in comparison with the known prototypes. In particular the mutant mini-intein Int4bPRO, containing the L93P mutation, has temperature-dependent properties. At cultivation temperature below 30 °C it allows the production of target molecules as part of soluble fusions, but after increasing of cultivation temperature to 37 °C it directs the most of synthesized fusions into insoluble intracellular aggregates. The transition of Int4bPRO into insoluble form is accompanied by complete inactivation of C-terminal processing. Further application of standard protein denaturation-renaturation procedures enable efficiently reactivate Int4bPRO and to carry out processing of its fusions in vitro. Two other variants, Int4b56 and Int4b36, containing a point mutation T62N or combination of mutations D144N and L146T respectively, have a reduced rate of C-terminal processing. Their use in E. coli cells allows to optimize the biosynthesis of biologically active target proteins and peptides in the composition of soluble fusions, suitable for afnne purification and subsequent intein-dependent processing without the use of protein denaturation-renaturation procedures. intein, fusion, processing, processing rate, gelonin The work was supported within the framework of the State Assignment no. 595-00003-19 PR.

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).

Sign in / Sign up

Export Citation Format

Share Document