scholarly journals Assessing bioavailability and genotoxicity of heavy metals and metallic nanoparticles simultaneously using dual-sensing Escherichia coli whole-cell bioreporters

2016 ◽  
Vol 59 (4) ◽  
pp. 661-668 ◽  
Author(s):  
Sunghoon Kim ◽  
Youngdae Yoon
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Metallic Nanoparticles ◽  
Whole Cell ◽  
Dual Sensing

scholarly journals Tuning a bi-enzymatic cascade reaction in Escherichia coli to facilitate NADPH regeneration for ε-caprolactone production

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jinghui Xiong ◽  
Hefeng Chen ◽  
Ran Liu ◽  
Hao Yu ◽  
Min Zhuo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Regeneration System ◽  
Nadph Regeneration ◽  
Whole Cell ◽  
Cyclohexanone Monooxygenase ◽  
Ribosome Binding ◽  
Ribosome Binding Sites ◽  
Whole Cell Biocatalyst ◽  
Substrate Tolerance

Abstractε-Caprolactone is a monomer of poly(ε-caprolactone) which has been widely used in tissue engineering due to its biodegradability and biocompatibility. To meet the massive demand for this monomer, an efficient whole-cell biocatalytic approach was constructed to boost the ε-caprolactone production using cyclohexanol as substrate. Combining an alcohol dehydrogenase (ADH) with a cyclohexanone monooxygenase (CHMO) in Escherichia coli, a self-sufficient NADPH-cofactor regeneration system was obtained. Furthermore, some improved variants with the better substrate tolerance and higher catalytic ability to ε-caprolactone production were designed by regulating the ribosome binding sites. The best mutant strain exhibited an ε-caprolactone yield of 0.80 mol/mol using 60 mM cyclohexanol as substrate, while the starting strain only got a conversion of 0.38 mol/mol when 20 mM cyclohexanol was supplemented. The engineered whole-cell biocatalyst was used in four sequential batches to achieve a production of 126 mM ε-caprolactone with a high molar yield of 0.78 mol/mol.

scholarly journals A Mechanism-Based Whole-Cell Screening Assay to Identify Inhibitors of Protein Export in Escherichia coli by the Sec Pathway

2012 ◽  
Vol 17 (4) ◽  
pp. 535-541 ◽  
Author(s):  
Gregory J. Crowther ◽  
S. Arshiya Quadri ◽  
Benjamin J. Shannon-Alferes ◽  
Wesley C. Van Voorhis ◽  
Henry Rosen
Keyword(s):  
Escherichia Coli ◽  
High Throughput Screening ◽  
Drug Target ◽  
Rapid Identification ◽  
Protein Synthesis Inhibitors ◽  
Screening Assay ◽  
Whole Cell ◽  
Sec Pathway ◽  
Associated Proteins ◽  
Pass Through

More than 20% of bacterial proteins are noncytoplasmic, and most of these pass through the SecYEG channel en route to the periplasm, cell membrane, or surrounding environment. The Sec pathway, encompassing SecYEG and several associated proteins (SecA, SecB, YidC, SecDFYajC), is of interest as a potential drug target because it is distinct from targets of current drugs, is essential for bacterial growth, and exhibits dissimilarities in eukaryotes and bacteria that increase the likelihood of selectively inhibiting the microbial pathway. As a step toward validating the pathway as a drug target, we have adapted a mechanism-based whole-cell assay in a manner suitable for high-throughput screening (HTS). The assay uses an engineered strain of Escherichia coli that accumulates beta-galactosidase (β-gal) in its cytoplasm if translocation through SecYEG is blocked. The assay should facilitate rapid identification of compounds that specifically block the Sec pathway because widely, toxic compounds and nonspecific protein synthesis inhibitors prevent β-gal production and thus do not register as hits. Testing of current antibiotics confirmed that they do not generally act through the Sec pathway. A mini-screen of 800 compounds indicated the assay’s readiness for larger screening projects.

scholarly journals Characterization of P450 FcpC, the Enzyme Responsible for Bioconversion of Diosgenone to Isonuatigenone in Streptomyces virginiae IBL-14

2009 ◽  
Vol 75 (12) ◽  
pp. 4202-4205 ◽  
Author(s):  
Wei Wang ◽  
Feng-Qing Wang ◽  
Dong-Zhi Wei
Keyword(s):  
Escherichia Coli ◽  
Electron Transfer ◽  
Cytochrome P450 ◽  
Cytochrome P450 Monooxygenase ◽  
P450 Monooxygenase ◽  
Whole Cell ◽  
Electron Transfer Chain ◽  
Streptomyces Virginiae ◽  
Transfer Chain

ABSTRACT A new cytochrome P450 monooxygenase, FcpC, from Streptomyces virginiae IBL-14 has been identified. This enzyme is found to be responsible for the bioconversion of a pyrano-spiro steroid (diosgenone) to a rare nuatigenin-type spiro steroid (isonuatigenone), which is a novel C-25-hydroxylated diosgenone derivative. A whole-cell P450 system was developed for the production of isonuatigenone via the expression of the complete three-component electron transfer chain in an Escherichia coli strain.

Permeabilizing Escherichia coli for whole cell biocatalyst with enhanced biotransformation ability from l-glutamate to GABA

2014 ◽  
Vol 107 ◽  
pp. 39-46 ◽  
Author(s):  
Wei-rui Zhao ◽  
Jun Huang ◽  
Chun-long Peng ◽  
Sheng Hu ◽  
Pi-yu Ke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Whole Cell ◽  
Whole Cell Biocatalyst
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