RESUMO
Biosensors based on allosteric transcription factors have been widely used in synthetic biology. In this study, we utilized the Acinetobacter ADP1 transcription factor PobR to develop a biosensor activating the PpobA promoter when bound to its natural ligand, 4-hydroxybenzoic acid (4HB). To screen for PobR mutants responsive to 4-hydroxyphenylpyruvate(HPP), we developed a dual selection system in E. coli. The positive selection of this system was used to enrich PobR mutants that identified the required ligands. The following negative selection eliminated or weakened PobR mutants that still responded to 4HB. Directed evolution of the PobR library resulted in a variant where PobRW177R was 5.1 times more reactive to 4-hydroxyphenylpyruvate than PobRWT. Overall, we developed an efficient dual selection system for directed evolution of biosensors.
Assuntos
Técnicas Biossensoriais , Ácidos Fenilpirúvicos , Transativadores , Transativadores/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Practical aqueous zinc-ion batteries require low-cost thin zinc anodes with long-term reversible stripping/depositing. However, thin zinc anodes encounter more severe issues than thick zinc, such as dendrites and uneven stripping, resulting in subpar performance and limited lifetimes. Here, this work proposes a three-in-one zinc anode obtained by a large-scale two-step method to address the above issues. In a three-in-one zinc anode, the copper foil as an inactive current collector solves the gradual reduction of the active area when only the pure zinc as an active current collector. This work develops an automatic electroplating device that can continuously deposit a zinc layer on a conducting foil to meet the demand for zinc-coated copper foils. The sodium carboxymethylcellulose (CMC)-zinc fluoride (ZnF2) protective layer prevents direct contact between zinc and separator, and provides a uniform and sufficient supply of zinc ions. The CMC-ZnF2-coated copper foil performs up to 3000 reversible zinc deposition/stripping cycles with a cumulative capacity of 6 Ah cm-2 and an average Coulombic efficiency of 99.94%. The Zn||ZnVO cell using the three-in-one anode achieved a high capacity retention of over 70% after 15 000 cycles. The proposed three-in-one anode and the automatic electroplating device will facilitate industrialization of practical thin zinc anodes.
RESUMO
Background: Cerebral infarction (CI) is a common brain disease in clinical practice, which is mainly due to the pathological environment of ischemia and hypoxia caused by difficult cerebral circulation perfusion function, resulting in ischemic necrosis of local brain tissue and neurological impairment. In traditional Chinese medicine (TCM) theory, CI is mainly due to blood stasis in the brain. Therefore, blood-activating and stasis-dissipating drugs are often used to treat CI in clinical practice. Salvia miltiorrhiza Bunge (SMB) is a kind of traditional Chinese medicine with good efficacy in promoting blood circulation and removing blood stasis, and treatment of CI with it is a feasible strategy. Based on the above analysis, we chose network pharmacology to investigate the feasibility of SMB in the treatment of CI and to study the possible molecular mechanisms by providing some reference for the treatment of CI with TCM. Methods: The active ingredients and related targets of SMB were obtained through the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, and CI-related targets were obtained from the GeneCards and DisGeNET databases. The target of SMB for the treatment of CI was obtained using Cytoscape software and visualized. GO and KEGG enrichment analysis was performed based on "clusterProfiler" within R, and the prediction results were validated by molecular docking technique. Results: By constructing a compound-target (C-T) network, it was found that the active components in SMB mainly treated CI by regulating key proteins such as AKT1, IL-6, and EGFR. These key proteins mainly involve in pathways such as immune regulation, cancer and lipid metabolism, such as lipid and atherosclerosis, chemical carcinogenesis-receptor activation pathways, and IL-17 signaling pathway. In the GO term, it mainly regulates the response to steroid hormones, membrane rafts, and G protein-amine receptor coupled activity. Eventually, we verified that the luteolin and tanshinone IIA components in SMB have a good possibility of action with AKT1 and IL-6 by in silico techniques, indicating that SMB has some scientificity in the treatment of CI. Conclusion: SMB mainly treats CI by regulating 94 proteins involved in lipid and atherosclerosis, chemical carcinogenesis-receptor activation, and IL-17 signaling pathway. Our research strategy provided a template for the drug development of TCM for the treatment of CI.