lux operon
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2022 ◽  
Author(s):  
Richard W Davis ◽  
Charlotte Muse ◽  
Heather Eggleston ◽  
Micaila Hill ◽  
Peter Panizzi

Streptococcus pyogenes (S. pyogenes) can thrive in its host during an infection, and, as a result, it must be able to respond to external stimuli and available carbon sources. The pre-clinical use of engineered pathogens capable of constitutive light production may provide real-time information on microbial-specific metabolic processes. Here we mapped the central metabolism of a luxABCDE-modified S. pyogenes Xen20 (Strep. Xen20) to its de novo synthesis of luciferase substrates as assessed by the rate of light production in response to different environmental triggers. Previous characterization predicted that the lux operon was under the myo-inositol iolE promotor. Here we show that supplementation with myo-inositol generated increased Xen20 luminescence. Surprisingly, when supplemented with infection-relevant carbon sources, such as glucose or glycine, light production was diminished. This was presumably due to the scavenging of pyruvate by L-lactate dehydrogenase (LDH). Inhibition of LDH by its inhibitor, oxamate, partially restored luminescent signal in the presence of glucose, presumably by allowing the resulting pyruvate to proceed to acetyl-coenzyme A (CoA). This phenomenon appeared specific to the lactic acid bacterial metabolism as glucose or glycine did not reduce signal in an analogous luxABCDE-modified Gram-positive pathogen, Staph. Xen29. The Strep. Xen20 cells produced light in a concentration-dependent manner, inversely related to the amount of glucose present. Taken together, our measures of microbial response could provide new information regarding the responsiveness of S. pyogenes metabolism to acute changes in its local environments and cellular health.


2021 ◽  
Author(s):  
Carola Gregor

AbstractThe bacterial bioluminescence system enables light production in living cells without an external luciferin. Due to its relatively low levels of light emission, many applications of bioluminescence imaging would benefit from an increase in brightness of this system. In this report a new approach of mutagenesis and screening of the involved proteins is described that is based on the identification of mutants with improved properties under rate-limiting reaction conditions. Multiple rounds of screening in Escherichia coli resulted in the operon ilux2 that contains 26 new mutations in the fatty acid reductase complex which provides the aldehyde substrate for the bioluminescence reaction. Chromosomal integration of ilux2 yielded an autonomously bioluminescent E. coli strain with 7-fold increased brightness compared to the previously described ilux operon. The ilux2 strain produces sufficient signal for the robust detection of individual cells and enables highly sensitive long-term imaging of bacterial propagation without a selection marker.


2021 ◽  
Vol 10 (4) ◽  
pp. 72-80
Author(s):  
D. B. Kuznetsov ◽  
A. Yu. Mironov ◽  
V. A. Neschislyaev ◽  
I. L. Volkhin ◽  
A. M. Korolyuk ◽  
...  

Introduction. E. coli strains are the main microorganisms used for the production of a number of important biopharmaceutical products. There are no natural sources of microwave radiation on Earth, as it is absorbed by the upper atmosphere. No one doubts the importance of studying the biological effect of microwave radiation. The number of publications devoted to this problem is growing every year, and new ideas for the use of microwaves in drug production technology are emerging.Aim. Reveal the main effects of microwave irradiation and develop a technology for microwave intensification of E. coli culture growth.Materials and methods. This study presents the results of atomic force microscopy, refractometry, NMR relaxometry, turbidimetry, and lumimetry, demonstrating the possibility of microwave intensification of the cultivation process.Results and discussion. It was found that microwave irradiation leads to changes in the mobility of protons and the adsorption of water molecules on biopolymers and cells. These are the main links in the mechanism of "non-thermal" microwave action. A single microwave irradiation, depending on a number of parameters, can decrease or increase the growth of biomass. Studies of the bioluminescence of the E. coli strain with the lux-operon have shown that the optimal processing conditions do not negatively affect the luciferase production and metabolic activity of cells. Conclusion. The intensification procedure using microwave radiation can be considered a promising method and can provide new ideas for various applications in biotechnology.


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Thomas Vannier ◽  
Pascal Hingamp ◽  
Floriane Turrel ◽  
Lisa Tanet ◽  
Magali Lescot ◽  
...  

Abstract Although bioluminescent bacteria are the most abundant and widely distributed of all light-emitting organisms, the biological role and evolutionary history of bacterial luminescence are still shrouded in mystery. Bioluminescence has so far been observed in the genomes of three families of Gammaproteobacteria in the form of canonical lux operons that adopt the CDAB(F)E(G) gene order. LuxA and luxB encode the two subunits of bacterial luciferase responsible for light-emission. Our deep exploration of public marine environmental databases considerably expands this view by providing a catalog of new lux homolog sequences, including 401 previously unknown luciferase-related genes. It also reveals a broader diversity of the lux operon organization, which we observed in previously undescribed configurations such as CEDA, CAED and AxxCE. This expanded operon diversity provides clues for deciphering lux operon evolution and propagation within the bacterial domain. Leveraging quantitative tracking of marine bacterial genes afforded by planetary scale metagenomic sampling, our study also reveals that the novel lux genes and operons described herein are more abundant in the global ocean than the canonical CDAB(F)E(G) operon.


2020 ◽  
Vol 164 ◽  
pp. 06006
Author(s):  
Galimzhan Duskaev ◽  
Dmitry Deryabin ◽  
Dianna Kosyan ◽  
Elena Rusakova ◽  
Kseniya Inchagova ◽  
...  

The purpose of this study was to assess the biological activity and antiquorum activity of extracts of Lamiaceae plants. Material and methods. Extracts of 4 medicinal plants of the Lamiáceae were used as test substances. Bioluminescent analysis were used on the model Escherichia coli MG1655 and antiquorum activity of medicinal plant extracts - on the model Chromobacterium violaceum ATCC 31532. Result. An analysis of the bioluminescent testing of Mentha piperita leaf aqueous extract showed no toxic effect throughout the entire record period over the entire concentration range. Low concentrations of analyte (0.625 mg/ml - 0.0097 mg/ml) cause a slight induction of lux-operon. Sālvia officinālis extract showed a slight antibacterial effect on the tested strain (EC50 = 10 mg/ml). The effect is achieved after 50-60 minutes of contact of microbial cells with components of Sālvia officinālis extract and persists until the end of the analyzed period of time (180 minutes). Extract of Oríganum vulgáre showed a decrease in the level of luminescence by 30% when the analyte was exposed to a concentration of 10 mg/ml. The extract of Thýmus serpýllum showed a pronounced antibacterial effect on the test organism, with a maximum concentration of 10 mg/ml, a 50% inhibition of luminescence is observed. All the tested compounds in subinhibitory concentrations suppressed the quorum-dependent biosynthesis of violacein.


2018 ◽  
Vol 24 (8) ◽  
pp. 952-958 ◽  
Author(s):  
Xiwen Wang ◽  
Hang Chi ◽  
Bo Zhou ◽  
Wenliang Li ◽  
Zhiping Li ◽  
...  

The bacterial luciferase gene cassette (lux) is an ideal bioreporter for real-time monitoring of the dynamics of bacteria because it is a fully autonomous, substrate-free bioluminescent reporter system available in a prokaryotic or eukaryotic host background. The lux operon is emerging as a powerful bioreporter for the study of a wide range of biological processes such as gene function, drug discovery and development, cellular trafficking, protein-protein interactions, and especially tumorigenesis and cancer treatment. Furthermore, the use of a high signal to noise bioluminescent bioreporter is quickly replacing traditional fluorescent bioreporter because of the lack of endogenous bioluminescent reactions in living animals. This review briefly describes how the lux operon is used for bioluminescence imaging. Current advances in bioluminescence bacteria development are summarized, focusing on their construction strategy and applications in bacterial infection and antibiotic treatment. Different construction methods of lux-expressing cell lines are also discussed. Taken together, this review provides valuable guidelines toward the development of an ideal bioluminescent bacteria or cell lines to evaluate the efficacy of a drug.


2017 ◽  
Vol 71 (0) ◽  
pp. 0-0
Author(s):  
Katarzyna Pajor ◽  
Daniel Sypniewski ◽  
Ilona Bednarek

Bioluminescence has been studied for many years by scientists. There are numerous mechanisms of that phenomenon; among them bacterial bioluminescence is the most frequently found in nature. This type of bioluminescence is determined by the appearance of lux operon, which encodes all elements necessary to produce light emission and it does not require any additional substrates supply. Another commonly found example of bioluminescence mechanism is performed by Photinus pyralis. Luciferase of P. pyralis named FLuc requires D-luciferin as a substrate. Bioluminescence is also characteristic for many deep-sea organisms. Most of them are based on oxidation reaction of coelenterazine to coelenteramide mediated by RLuc or GLuc luciferases. Due to the variety of bioluminescence mechanisms in nature, it has become possible to apply them in many sensitive methods that can be used in molecular biology and medicine. The most significant application of bioluminescence is BLI (bioluminescence imaging). This method is cheap and nontoxic which allows both in vitro and in vivo imaging. BLI applications include, e.g. protein-protein interactions, stem cells labeling, tracking of viral, bacterial, fungal and parasitical infections, and carcinogenesis analyses. Bioluminescence has also been used in the creation of modified cell systems capable of light emission in response to certain analytes and thus very sensitive biosensors have been generated. Other important areas of bioluminescence application are immunoassays, ATP assays, and BART analysis (bioluminescent assay in Real-Time) – a very sensitive technique which allows scientists to estimate nucleic acids amplification.


2016 ◽  
Vol 14 (4) ◽  
pp. 52 ◽  
Author(s):  
Elena V Igonina ◽  
Mariya V Marsova ◽  
Serikbai K Abilev

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.


Microbiology ◽  
2016 ◽  
Vol 162 (4) ◽  
pp. 717-724 ◽  
Author(s):  
Svetlana A. Khrulnova ◽  
Ancha Baranova ◽  
Sergey V. Bazhenov ◽  
Ignatiy I. Goryanin ◽  
Maria N. Konopleva ◽  
...  

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