scholarly journals A Constitutive Expression System for Cellulase Secretion in Escherichia coli and Its Use in Bioethanol Production

PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0119917 ◽  
Author(s):  
Neha Munjal ◽  
Kamran Jawed ◽  
Saima Wajid ◽  
Syed Shams Yazdani
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Constitutive Expression ◽  
Bioethanol Production ◽  
Cellulase Secretion

scholarly journals Constructing a DNAzyme Delivery and Expression System for Escherichia coli: A Prototype for Phage Therapy

2021 ◽  
Vol 2 (2) ◽  
pp. 19-25
Author(s):  
Hugo V. C. Oliveira ◽  
Spartaco Astolfi-Filho ◽  
Edmar V. Andrade
Keyword(s):  
Escherichia Coli ◽  
Protein Delivery ◽  
Phage Therapy ◽  
Leukemia Virus ◽  
Expression System ◽  
Constitutive Expression ◽  
Primary Component ◽  
Morphological Pattern ◽  
Filamentous Form ◽  
E Coli

Antisense oligonucleotides exhibit high potential for use as therapeutic agents. '10-23' DNAzymes are antisense molecules with a high chemical stability and catalytic efficiency. In the present study, we developed a phagemid containing a DNAzyme expression system regulated by two promoters. One of these promoters, pA1, promotes constitutive expression of Moloney murine leukemia virus reverse transcriptase (MoMuLV-RT). The other promoter, plac, regulates transcription of the RNA substrate from which MoMuLV-RT produces the DNAzyme by reverse transcription. The ftsZ DNAzyme was used to validate this expression system in the phagemid, named pDESCP. ftsZ DNAzyme expression altered the morphological pattern of Escherichia coli from a bacillary to filamentous form. In E. coli FtsZ is the primary component of the cell division apparatus, forming a structure known as Z-ring, which is the place of division. It is suggested that the DNAzyme ftsZ is decreasing the translation of this protein. Delivery of pDESCP into F+ strain of E. coli cells, using VCSM13, and the possible insertion of other DNAzymes into the cassette makes this phagemid an important prototype for phage therapy.

scholarly journals A novel process for obtaining phenylpropanoic acid precursor using Escherichia coli with a constitutive expression system

2016 ◽  
Vol 25 (3) ◽  
pp. 795-801
Author(s):  
Jing-long Liang ◽  
Liqiong Guo ◽  
Ping Sun ◽  
Binghua Jiang ◽  
Junfang Lin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Constitutive Expression ◽  
Acid Precursor

An efficient dsRNA constitutive expression system in Escherichia coli

2021 ◽  
Vol 105 (16-17) ◽  
pp. 6381-6393
Author(s):  
Josemaría Delgado-Martín ◽  
Leonardo Velasco
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Constitutive Expression

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

scholarly journals Functional expression of the eukaryotic proton pump rhodopsin OmR2 in Escherichia coli and its photochemical characterization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masuzu Kikuchi ◽  
Keiichi Kojima ◽  
Shin Nakao ◽  
Susumu Yoshizawa ◽  
Shiho Kawanishi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Proton Pump ◽  
Expression System ◽  
Spectroscopic Characterization ◽  
Functional Expression ◽  
Proton Pumping ◽  
E Coli ◽  
Oxyrrhis Marina ◽  
Domains Of Life

AbstractMicrobial rhodopsins are photoswitchable seven-transmembrane proteins that are widely distributed in three domains of life, archaea, bacteria and eukarya. Rhodopsins allow the transport of protons outwardly across the membrane and are indispensable for light-energy conversion in microorganisms. Archaeal and bacterial proton pump rhodopsins have been characterized using an Escherichia coli expression system because that enables the rapid production of large amounts of recombinant proteins, whereas no success has been reported for eukaryotic rhodopsins. Here, we report a phylogenetically distinct eukaryotic rhodopsin from the dinoflagellate Oxyrrhis marina (O. marina rhodopsin-2, OmR2) that can be expressed in E. coli cells. E. coli cells harboring the OmR2 gene showed an outward proton-pumping activity, indicating its functional expression. Spectroscopic characterization of the purified OmR2 protein revealed several features as follows: (1) an absorption maximum at 533 nm with all-trans retinal chromophore, (2) the possession of the deprotonated counterion (pKa = 3.0) of the protonated Schiff base and (3) a rapid photocycle through several distinct photointermediates. Those features are similar to those of known eukaryotic proton pump rhodopsins. Our successful characterization of OmR2 expressed in E. coli cells could build a basis for understanding and utilizing eukaryotic rhodopsins.

scholarly journals Optimizing the Production of Recombinant Hydroperoxide Lyase in Escherichia coli Using Statistical Design

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 176
Author(s):  
Sophie Vincenti ◽  
Magali Mariani ◽  
Jessica Croce ◽  
Eva Faillace ◽  
Virginie Brunini-Bronzini de Caraffa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Scale Up ◽  
Food Additives ◽  
Statistical Design ◽  
Green Leaf Volatiles ◽  
Hydroperoxide Lyase ◽  
Soluble Enzyme ◽  
Leaf Volatiles ◽  
Conversion Rates

Hydroperoxide lyase (HPL) catalyzes the synthesis of volatiles C6 or C9 aldehydes from fatty acid hydroperoxides. These short carbon chain aldehydes, known as green leaf volatiles (GLV), are widely used in cosmetic industries and as food additives because of their “fresh green” aroma. To meet the growing demand for natural GLVs, the use of recombinant HPL as a biocatalyst in enzyme-catalyzed processes appears to be an interesting application. Previously, we cloned and expressed a 13-HPL from olive fruit in Escherichia coli and showed high conversion rates (up to 94%) during the synthesis of C6 aldehydes. To consider a scale-up of this process, optimization of the recombinant enzyme production is necessary. In this study, four host-vector combinations were tested. Experimental design and response surface methodology (RSM) were used to optimize the expression conditions. Three factors were considered, i.e., temperature, inducer concentration and induction duration. The Box–Behnken design consisted of 45 assays for each expression system performed in deep-well microplates. The regression models were built and fitted well to the experimental data (R2 coefficient > 97%). The best response (production level of the soluble enzyme) was obtained with E. coli BL21 DE3 cells. Using the optimal conditions, 2277 U L−1of culture of the soluble enzyme was produced in microliter plates and 21,920 U L−1of culture in an Erlenmeyer flask, which represents a 79-fold increase compared to the production levels previously reported.

Viability and survival capability of quinolone-resistant uropathogenic Escherichia coli

2010 ◽  
Vol 5 (6) ◽  
pp. 827-830
Author(s):  
Georgi Slavchev ◽  
Nadya Markova
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Expression System ◽  
Antibiotic Sensitivity ◽  
Uropathogenic Escherichia Coli ◽  
Resistant Bacteria ◽  
E Coli ◽  
Serum Bactericidal Assay ◽  
Tract Infections ◽  
Macrophage Killing

AbstractUropathogenic strains of E. coli isolated from urine of patients with urinary tract infections were tested for antibiotic sensitivity using bio-Merieux kits and ATB-UR 5 expression system. The virulence of strains was evaluated by serum bactericidal assay, macrophage “killing” and bacterial adhesive tests. Survival capability of strains was assessed under starvation in saline. The results showed that quinolone-resistant uropathogenic strains of E. coli exhibit significantly reduced adhesive potential but relatively high resistance to serum and macrophage bactericidity. In contrast to laboratory strains, the quinolone-resistant uropathogenic clinical isolate demonstrated increased viability during starvation in saline. Our study suggests that quinolone-resistant uropathogenic strains are highly adaptable clones of E. coli, which can exhibit compensatory viability potential under unfavorable conditions. The clinical occurrence of such phenotypes is likely to contribute to the survival, persistence and spread strategy of resistant bacteria.

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