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1.
Ibrain ; 9(3): 326-339, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37786754

RESUMO

Cerebral ischemia is a serious cerebrovascular disease with the characteristics of high morbidity, disability, and mortality. Currently, stem cell therapy has been extensively applied to a wide range of diseases, including neurological disorders, autoimmune deficits, and other diseases. Transplantation therapy with neural stem cells (NSCs) is a very promising treatment method, which not only has anti-inflammatory, antiapoptotic, promoting angiogenesis, and neurogenesis effects, but also can improve some side effects related to thrombolytic therapy. NSCs treatment could exert protective effects in alleviating cerebral ischemia-induced brain damage and neurological dysfunctions. However, the different injection routes and doses of NSCs determine diverse therapeutic efficacy. This review mainly summarizes the various injection methods and injection effects of NSCs in cerebral ischemia, as well as proposes the existing problems and prospects of NSCs transplantation.

2.
Anal Chem ; 95(26): 9734-9738, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37341424

RESUMO

Monitoring and tracing of regulated hazardous chemicals is a public security issue of global concern. However, accurately recording historical exposure remains challenging. Here, we designed a Biological Sentinel System (BOSS) for in situ and long-term monitoring of hazardous chemical exposure using a chemical-induced base-editing system that activates antibiotic resistance screening, producing an obvious colorimetric signal. Exposure events can be written into an inheritable genomic DNA sequence, which can be read using gene sequencing. As a proof of concept, we demonstrated the accurate detection of cocaine and 2,4-dinitrotoluene using BOSS under simulated application scenarios. In addition, we integrated alternative biosensors to illustrate the modularity and extensibility of this monitoring platform. This work provides a promising paradigm for developing engineered microorganisms as an alternative to electronic monitors for regulated hazardous chemicals.


Assuntos
Bactérias , Substâncias Perigosas , Bactérias/genética
3.
Biotechnol Appl Biochem ; 70(2): 798-810, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36070874

RESUMO

Sulforaphane (SFN), a defense secondary metabolite, can be used to predict the health status of plants and also has pharmacological effects, including anticancer, antioxidant, and anti-inflammatory properties. The detection of SFN is therefore of great significance for the prevention and treatment of diseases. In this study, a "turn off" whole-cell biosensor that can rapidly and robustly respond to the presence of SFN was constructed based on the orthogonal genetic components (hrpR, hrpS, and PhrpL ) of Pseudomonas syringae (PS). The final optimized biosensor, p114(30R-30S), was able to inhibit 91.7% of the fluorescence intensity in the presence of 100-µM SFN. Subsequently, a HrpRS-regulated OFF-ON genetic switch was designed by reconstituting a reverse σ70 promoter on the σ54 -PhrpL promoter sequence; this was coupled with dual-color reporter genes to construct a "turn off-on" whole-cell SFN biosensor. The PhrpLB variant increased the expression of green fluorescence a factor of 11.9 and reduced the expression of red fluorescence by 85.8% compared with the system in the absence of SFN. Thus, a robust switching of signal output from "turn off" to "turn on" was realized. In addition, the biosensor showed good linearity in the SFN concentration ranges of 0.1-10 µM (R2  = 0.99429) and 10-100 µM (R2  = 0.99465) and a detection limit of ~0.1 µM.


Assuntos
Proteínas de Bactérias , Fatores de Transcrição , Fatores de Transcrição/metabolismo , Proteínas de Bactérias/genética , Isotiocianatos/farmacologia , Sulfóxidos
4.
Front Cell Infect Microbiol ; 12: 1044770, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36506032

RESUMO

Purpose: 2019 Coronavirus disease (COVID-19) is endangering health of populations worldwide. Latest research has proved that Lianhua Qingwen granules (LHQW) can reduce tissue damage caused by inflammatory reactions and relieve patients' clinical symptoms. However, the mechanism of LHQW treats COVID-19 is currently lacking. Therefore, we employed computer simulations to investigate the mechanism of LHQW treats COVID-19 by modulating inflammatory response. Methods: We employed bioinformatics to screen active ingredients in LHQW and intersection gene targets. PPI, GO and KEGG was used to analyze relationship of intersection gene targets. Molecular dynamics simulations validated the binding stability of active ingredients and target proteins. Binding free energy, radius of gyration and the solvent accessible surface area were analyzed by supercomputer platform. Results: COVID-19 had 4628 gene targets, LHQW had 1409 gene targets, intersection gene targets were 415. Bioinformatics analysis showed that intersection targets were closely related to inflammation and immunomodulatory. Molecular docking suggested that active ingredients (including: licopyranocoumarin, Glycyrol and 3-3-Oxopropanoic acid) in LHQW played a role in treating COVID-19 by acting on CSF2, CXCL8, CCR5, NLRP3, IFNG and TNF. Molecular dynamics was used to prove the binding stability of active ingredients and protein targets. Conclusion: The mechanism of active ingredients in LHQW treats COVID-19 was investigated by computer simulations. We found that active ingredients in LHQW not only reduce cell damage and tissue destruction by inhibiting the inflammatory response through CSF2, CXCL8, CCR5 and IFNG, but also regulate cell survival and growth through NLRP3 and TNF thereby reducing apoptosis.


Assuntos
COVID-19 , Simulação de Dinâmica Molecular , Humanos , Simulação de Acoplamento Molecular , Sobrevivência Celular , Biologia Computacional
5.
Front Microbiol ; 13: 1013911, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36329841

RESUMO

Purpose: 2019 Coronavirus disease (COVID-19) has caused millions of confirmed cases and deaths worldwide. TMPRSS2-mediated hydrolysis and maturation of spike protein is essential for SARS-CoV-2 infection in vivo. The latest research found that a TMPRSS2 inhibitor called N-0385 could effectively prevent the infection of the SARS-CoV-2 and its variants. However, it is not clear about the mechanism of N-0385 treatment COVID-19. Therefore, this study used computer simulations to investigate the mechanism of N-0385 treatment COVID-19 by impeding SARS-CoV-2 infection. Methods: The GeneCards database was used to search disease gene targets, core targets were analyzed by PPI, GO and KEGG. Molecular docking and molecular dynamics were used to validate and analyze the binding stability of small molecule N-0385 to target proteins. The supercomputer platform was used to simulate and analyze the number of hydrogen bonds, binding free energy, stability of protein targets at the residue level, radius of gyration and solvent accessible surface area. Results: There were 4,600 COVID-19 gene targets from GeneCards database. PPI, GO and KEGG analysis indicated that signaling pathways of immune response and inflammation played crucial roles in COVID-19. Molecular docking showed that N-0385 could block SARS-CoV-2 infection and treat COVID-19 by acting on ACE2, TMPRSS2 and NLRP3. Molecular dynamics was used to demonstrate that the small molecule N-0385 could form very stable bindings with TMPRSS2 and TLR7. Conclusion: The mechanism of N-0385 treatment COVID-19 was investigated by molecular docking and molecular dynamics simulation. We speculated that N-0385 may not only inhibit SARS-CoV-2 invasion directly by acting on TMPRSS2, ACE2 and DPP4, but also inhibit the immune recognition process and inflammatory response by regulating TLR7, NLRP3 and IL-10 to prevent SARS-CoV-2 invasion. Therefore, these results suggested that N-0385 may act through multiple targets to reduce SARS-CoV-2 infection and damage caused by inflammatory responses.

6.
Steroids ; 188: 109131, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36273543

RESUMO

PURPOSE: Spinal cord injury can lead to incomplete or complete loss of voluntary movement and sensory function, leading to serious complications. Numerous studies have shown that progesterone exhibits strong therapeutic potential for spinal cord injury. However, the mechanism by which progesterone treats spinal cord injury remains unclear. Therefore, this article explores the mechanism of progesterone in the treatment of spinal cord injury by means of molecular docking and molecular dynamics simulation. METHODS: We used bioinformatics to screen active pharmaceutical ingredients and potential targets, and molecular docking and molecular dynamics were used to validate and analysis by the supercomputer platform. RESULTS: Progesterone had 3606 gene targets, spinal cord injury had 6560 gene targets, the intersection gene targets were 2355. GO and KEGG analysis showed that the abundant pathways involved multiple pathways related to cell metabolism and inflammation. Molecular docking showed that progesterone played a role in treating spinal cord injury by acting on BDNF, AR, NGF and TNF. Molecular dynamics was used to prove and analyzed the binding stability of active ingredients and protein targets, and AR/Progesterone combination has the strongest binding energy. CONCLUSION: Progesterone promotes recovery from spinal cord injury by promoting axonal regeneration, remyelination, neuronal survival and reducing inflammation.


Assuntos
Progesterona , Traumatismos da Medula Espinal , Humanos , Progesterona/farmacologia , Progesterona/uso terapêutico , Progesterona/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/metabolismo , Preparações Farmacêuticas , Inflamação/tratamento farmacológico
7.
Front Physiol ; 13: 990469, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105284

RESUMO

Purpose: Dapansutrile is an orally active ß-sulfonyl nitrile compound that selectively inhibits the NLRP3 inflammasome. Clinical studies have shown that dapansutrile is active in vivo and limits the severity of endotoxin-induced inflammation and joint arthritis. However, there is currently a lack of more in-depth research on the effect of dapansutrile on protein targets such as NLRP3 in gouty arthritis. Therefore, we used molecular docking and molecular dynamics to explore the mechanism of dapansutrile on NLRP3 and other related protein targets. Methods: We use bioinformatics to screen active pharmaceutical ingredients and potential disease targets. The disease-core gene target-drug network was established and molecular docking was used for verification. Molecular dynamics simulations were utilized to verify and analyze the binding stability of small molecule drugs to target proteins. The supercomputer platform was used to measure and analyze the binding free energy, the number of hydrogen bonds, the stability of the protein target at the residue level, the radius of gyration and the solvent accessible surface area. Results: The protein interaction network screened out the core protein targets (such as: NLRP3, TNF, IL1B) of gouty arthritis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that gouty arthritis mainly played a vital role by the signaling pathways of inflammation and immune response. Molecular docking showed that dapansutrile play a role in treating gouty arthritis by acting on the related protein targets such as NLRP3, IL1B, IL6, etc. Molecular dynamics was used to prove and analyze the binding stability of active ingredients and protein targets, the simulation results found that dapansutrile forms a very stable complex with IL1B. Conclusion: We used bioinformatics analysis and computer simulation system to comprehensively explore the mechanism of dapansutrile acting on NLRP3 and other protein targets in gouty arthritis. This study found that dapansutrile may not only directly inhibit NLRP3 to reduce the inflammatory response and pyroptosis, but also hinder the chemotaxis and activation of inflammatory cells by regulating IL1B, IL6, IL17A, IL18, MMP3, CXCL8, and TNF. Therefore, dapansutrile treats gouty arthritis by attenuating inflammatory response, inflammatory cell chemotaxis and extracellular matrix degradation by acting on multiple targets.

8.
Front Pharmacol ; 13: 1003310, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36120307

RESUMO

Purpose: The rapid worldwide spread of Corona Virus Disease 2019 (COVID-19) has become not only a global challenge, but also a lack of effective clinical treatments. Studies have shown that licorice can significantly improve clinical symptoms such as fever, dry cough and shortness of breath in COVID-19 patients with no significant adverse effects. However, there is still a lack of in-depth analysis of the specific active ingredients of licorice in the treatment of COVID-19 and its mechanism of action. Therefore, we used molecular docking and molecular dynamics to explore the mechanism of action of licorice in the treatment of COVID-19. Methods: We used bioinformatics to screen active pharmaceutical ingredients and potential targets, the disease-core gene target-drug network was established and molecular docking was used for verification. Molecular dynamics simulations were carried out to verify that active ingredients were stably combined with protein targets. The supercomputer platform was used to measure and analyze stability of protein targets at the residue level, solvent accessible surface area, number of hydrogen bonds, radius of gyration and binding free energy. Results: Licorice had 255 gene targets, COVID-19 had 4,628 gene targets, the intersection gene targets were 101. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene ontology (GO) analysis showed that licorice played an important role mainly through the signaling pathways of inflammatory factors and oxidative stress. Molecular docking showed that Glycyrol, Phaseol and Glyasperin F in licorice may playe a role in treating COVID-19 by acting on STAT3, IL2RA, MMP1, and CXCL8. Molecular dynamics were used to demonstrate and analyze the binding stability of active ingredients to protein targets. Conclusion: This study found that Phaseol in licorice may reduce inflammatory cell activation and inflammatory response by inhibiting the activation of CXCL8 and IL2RA; Glycyrol may regulate cell proliferation and survival by acting on STAT3. Glyasperin F may regulate cell growth by inhibiting the activation of MMP1, thus reducing tissue damage and cell death caused by excessive inflammatory response and promoting the growth of new tissues. Therefore, licorice is proposed as an effective candidate for the treatment of COVID-19 through STAT3, IL2RA, MMP1, and CXCL8.

9.
Artigo em Inglês | MEDLINE | ID: mdl-35990842

RESUMO

Purpose: The research aims to investigate the mechanism of action of aspirin in the treatment of Kawasaki disease. Methods: We predicted the targets of aspirin with the help of the Drugbank and PharmMapper databases, the target genes of Kawasaki disease were mined in the GeneCards and Disgenet databases, the intersection targets were processed in the Venny database, and the gene expression differences were observed in the GEO database. The Drugbank and PharmMapper databases were used to predict the target of aspirin, and the target genes of Kawasaki disease were explored in the GeneCards and Disgenet databases, and the Venny was used for intersection processing. We observed the gene expression differences in the GEO database. The disease-core gene target-drug network was established and molecular docking was used for verification. Molecular dynamics simulation verification was carried out to combine the active ingredient and the target with a stable combination. The supercomputer platform was used to measure and analyze the binding free energy, the number of hydrogen bonds, the stability of the protein target at the residue level, the radius of gyration, and the solvent accessible surface area. Results: Aspirin had 294 gene targets, Kawasaki disease had 416 gene targets, 42 intersecting targets were obtained, we screened 13 core targets by PPI; In the GO analysis, we learned that the biological process of Kawasaki disease involved the positive regulation of chemokine biosynthesis and inflammatory response; pathway enrichment involved PI3K-AKT signaling pathway, tumor necrosis factor signaling pathway, etc. After molecular docking, the data showed that CTSG, ELANE, and FGF1 had the best binding degree to aspirin. Molecular dynamics was used to prove and analyze the binding stability of active ingredients and protein targets, and Aspirin/ELANE combination has the strongest binding energy. Conclusion: In the treatment of Kawasaki disease, aspirin may regulate inflammatory response and vascular remodeling through CTSG, ELANE, and FGF1.

10.
Front Cell Infect Microbiol ; 12: 965273, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36034710

RESUMO

Purpose: The Corona Virus Disease 2019 (COVID-19) pandemic has become a challenge of world. The latest research has proved that Xuanfei Baidu granule (XFBD) significantly improved patient's clinical symptoms, the compound drug improves immunity by increasing the number of white blood cells and lymphocytes, and exerts anti-inflammatory effects. However, the analysis of the effective monomer components of XFBD and its mechanism of action in the treatment of COVID-19 is currently lacking. Therefore, this study used computer simulation to study the effective monomer components of XFBD and its therapeutic mechanism. Methods: We screened out the key active ingredients in XFBD through TCMSP database. Besides GeneCards database was used to search disease gene targets and screen intersection gene targets. The intersection gene targets were analyzed by GO and KEGG. The disease-core gene target-drug network was analyzed and molecular docking was used for verification. Molecular dynamics simulation verification was carried out to combine the active ingredient and the target with a stable combination. The supercomputer platform was used to measure and analyze the number of hydrogen bonds, the binding free energy, the stability of protein target at the residue level, the solvent accessible surface area, and the radius of gyration. Results: XFBD had 1308 gene targets, COVID-19 had 4600 gene targets, the intersection gene targets were 548. GO and KEGG analysis showed that XFBD played a vital role by the signaling pathways of immune response and inflammation. Molecular docking showed that I-SPD, Pachypodol and Vestitol in XFBD played a role in treating COVID-19 by acting on NLRP3, CSF2, and relieve the clinical symptoms of SARS-CoV-2 infection. Molecular dynamics was used to prove the binding stability of active ingredients and protein targets, CSF2/I-SPD combination has the strongest binding energy. Conclusion: For the first time, it was found that the important active chemical components in XFBD, such as I-SPD, Pachypodol and Vestitol, reduce inflammatory response and apoptosis by inhibiting the activation of NLRP3, and reduce the production of inflammatory factors and chemotaxis of inflammatory cells by inhibiting the activation of CSF2. Therefore, XFBD can effectively alleviate the clinical symptoms of COVID-19 through NLRP3 and CSF2.


Assuntos
Tratamento Farmacológico da COVID-19 , Medicamentos de Ervas Chinesas , SARS-CoV-2 , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Humanos , Medicina Tradicional Chinesa , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Proteína 3 que Contém Domínio de Pirina da Família NLR , SARS-CoV-2/efeitos dos fármacos
11.
Anal Chem ; 94(20): 7210-7218, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35537205

RESUMO

Whole-cell biosensors for arsenic contamination are typically designed based on natural bacterial sensing systems, which are often limited by their poor performance for precisely tuning the genetic response to environmental stimuli. Promoter design remains one of the most important approaches to address such issues. Here, we use the arsenic-responsive ArsR-Pars regulation system from Escherichia coli MG1655 as the sensing element and coupled gfp or lacZ as the reporter gene to construct the genetic circuit for characterizing the refactored promoters. We first analyzed the ArsR binding site and a library of RNA polymerase binding sites to mine potential promoter sequences. A set of tightly regulated Pars promoters by ArsR was designed by placing the ArsR binding sites into the promoter's core region, and a novel promoter with maximal repression efficiency and optimal fold change was obtained. The fluorescence sensor PlacV-ParsOC2 constructed with the optimized ParsOC2 promoter showed a fold change of up to 63.80-fold (with green fluorescence visible to the naked eye) at 9.38 ppb arsenic, and the limit of detection was as low as 0.24 ppb. Further, the optimized colorimetric sensor PlacV-ParsOC2-lacZ with a linear response between 0 and 5 ppb was used to perform colorimetric reactions in 24-well plates combined with a smartphone application for the quantification of the arsenic level in groundwater. This study offers a new approach to improve the performance of bacterial sensing promoters and will facilitate the on-site application of arsenic whole-cell biosensors.


Assuntos
Arsênio , Técnicas Biossensoriais , Proteínas de Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Genes Reporter , Regiões Promotoras Genéticas , Transativadores
12.
Biosens Bioelectron ; 207: 114205, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35339074

RESUMO

The detection of mine-based explosives poses a serious threat to the lives of deminers, and carcinogenic residues may cause severe environmental pollution. Whole-cell biosensors that can detect on-site in dangerous or inaccessible environments have great potential to replace conventional methods. Synthetic biology based on engineering modularity serves as a new tool that could be used to engineer microbes to acquire desired functions through artificial design and precise regulation. In this study, we designed artificial genetic circuits in Escherichia coli MG1655 by reconstructing the transcription factor YhaJ-based system to detect explosive composition 2,4-dinitrotoluene (2,4-DNT). These genetic circuits were optimized at the transcriptional, translational, and post-translational levels. The binding affinity of the transcription factor YhaJ with inducer 2,4-DNT metabolites was enhanced via directed evolution, and several activator binding sites were inserted in sensing yqjF promoter (PyqjF) to further improve the output level. The optimized biosensor PyqjF×2-TEV-(mYhaJ + GFP)-Ssr had a maximum induction ratio of 189 with green fluorescent signal output, and it could perceive at least 1 µg/mL 2,4-DNT. Its effective and robust performance was verified in different water samples. Our results demonstrate the use of synthetic biology tools to systematically optimize the performance of sensors for 2,4-DNT detection, that lay the foundation for practical applications.


Assuntos
Técnicas Biossensoriais , Substâncias Explosivas , Técnicas Biossensoriais/métodos , Dinitrobenzenos , Escherichia coli/genética , Escherichia coli/metabolismo , Substâncias Explosivas/metabolismo , Fatores de Transcrição/genética
13.
J Med Microbiol ; 71(1)2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35020583

RESUMO

Introduction. Biofilms are the natural growth state for most microorganisms. C. albicans biofilms are composed of multiple cell types (round budding yeast-form cells, oval pseudohyphal cells, and elongated hyphal cells) encased in an extracellular matrix. C. albicans biofilms are notorious for resistance to antimicrobial treatments, a property that might be determined by complex mechanisms. Exogenous farnesol exerts a certain antifungal activity against C. albicans with medical implications. Different from other microbes, C. albicans biofilms can tolerate exogenous farnesol at high concentration with some cells still surviving and even maintaining proliferation, but the mechanism is unclear.Hypothesis. The study hypothesizes that C. albicans resists farnesol by activating the PKC signalling pathway.Aim. The study aims to discuss the molecular mechanism of C. albicans resistance to farnesol.Methodology. The ROS levels, the genes and proteins of the PKC pathway were compared between the farnesol-tolerant and non-tolerant groups using ROS levels assay, q-RT PCR and Western blot, respectively. Further, the mutant strains (pkc1Δ/Δ and mkc1Δ/Δ) were constructed, then the survival rates and ROS levels of biofilms exposed to farnesol were compared between mutant and wild strains. The morphological changes were observed using TEM.Results. The survival rates of C. albicans biofilms decreased rapidly under the lower concentration of farnesol (P<0.05), and kept stable (P>0.05) as the concentration rose up to 200 µM. The gene expression of the PKC pathway increased, while ROS levels remained stable and even decreased in the farnesol-tolerant biofilms, compared with those in the farnesol-nontolerant biofilms after farnesol treatment (P<0.05); pkc1 and mkc1 were significantly upregulated by C. albicans during the development of biofilm tolerance to farnesol. The cell wall and cytoplasm of pkc1Δ/Δ and mkc1Δ/Δ were damaged, and the ROS level increased (P<0.05); meanwhile, the survival rate of biofilms decreased compared with that of wild-type strain under the same farnesol concentrations (P<0.05). ROS inhibitors reversed these changes in pkc1Δ/Δ and mkc1Δ/Δ when the mutant strains exposed to farnesol.Conclusion. C. albicans biofilms can tolerate high concentrations of farnesol by activating pkc1 and mkc1 of the PKC pathway and stabilizing ROS levels. The pkc1 and mkc1 are two key genes regulated by C. albicans in the process of biofilm tolerance to farnesol.


Assuntos
Biofilmes , Candida albicans , Farneseno Álcool , Proteína Quinase C , Transdução de Sinais , Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Farneseno Álcool/farmacologia , Regulação Fúngica da Expressão Gênica , Proteína Quinase C/metabolismo , Espécies Reativas de Oxigênio/metabolismo
14.
ACS Synth Biol ; 8(10): 2295-2302, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31525958

RESUMO

Whole-cell biosensors have attracted considerable interests because they are robust, eco-friendly, and cost-effective. However, most of the biosensors harness the naturally occurring wild-type promoter, which often suffers from high background noise and low sensitivity. In this study, we demonstrate how to design the core elements (i.e., RNA polymerase binding site and transcription factor binding site) of the promoters to obtain a significant gain in the signal-to-noise output ratio of the whole-cell biosensor circuits. As a proof of concept, we modified the arsenite-regulated promoter from Escherichia coli K-12 genome, such that it has a lower background and higher expression. This was achieved by balancing the relationship between the number of ArsR binding sites (ABS) and the activity of the promoter and adjusting the location of the auxiliary ABS. A promoter variant ParsD-ABS-8 was obtained with an induction ratio of 179 (11-fold increase over the wild-type promoter) when induced with 1 µM arsenite. Importantly, the developed biosensor exhibited good dose-response in the range of 0.1 to 4 µM (R2 = 0.9928) of arsenite with a detection limit of ca. 10 nM. These results indicated that the engineered promoter modification approach could be used to improve the performance of whole-cell biosensors, thereby facilitating their practical application.


Assuntos
Arsenitos/metabolismo , Técnicas Biossensoriais/métodos , Regiões Promotoras Genéticas/genética , Sítios de Ligação/genética , Escherichia coli K12/genética , Escherichia coli K12/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Genes Reporter/genética
15.
Bio Protoc ; 9(23): e3461, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-33654947

RESUMO

Candida albicans is the most common cause of fungal infections worldwide. Infection by C. albicans is closely associated with its ability to form a biofilm, closely packed communities of cells attached to the surfaces of human tissues and implanted devices, in or on the host. When tested for susceptibility to antifungals, such as polyenes, azoles, and allylamines, C. albicans cells in a biofilm are more resistant to antifungal agents than C. albicans cells in the planktonic form. Cyclic Adenosine monophosphate (cAMP) is one of the key elements for triggering hyphal and biofilm formation in C. albicans. It is hard to detect or extract molecular markers (e.g., cAMP) from C. albicans biofilms because the biofilms have a complex three-dimensional architecture with an extracellular matrix surrounding the cell walls of the cells in the biofilm. Here, we present an improved protocol that can effectively measure the level of intracellular cAMP in C. albicans biofilms.

16.
BMC Microbiol ; 18(1): 203, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30509171

RESUMO

BACKGROUND: Farnesol has potential antifungal activity against Candida albicans biofilms, but the molecular mechanism of this activity is still unclear. Farnesol inhibits hyphal growth by regulating the cyclic AMP (cAMP) signalling pathway in C. albicans, and CYR1 and PDE2 regulate a pair of enzymes that are directly responsible for cAMP synthesis and degradation. Here, we hypothesize that farnesol enhances the antifungal susceptibility of C. albicans biofilms by regulating CYR1 and PDE2. RESULTS: The resistance of the CYR1- and PDE2-overexpressing strains to caspofungin, itraconazole and terbinafine was increased in planktonic cells, and that to amphotericin B was increased in biofilms. Meanwhile, the biofilms of the CYR1- and PDE2-overexpressing strains were thicker (all p < 0.05) and consisted of more hyphae than that of the wild strain. The intracellular cAMP levels were higher in the biofilms of the CYR1-overexpressing strain than that in the biofilms of the wild strain (all p < 0.01), while no changes were found in the PDE2-overexpressing strain. Exogenous farnesol decreased the resistance of the CYR1- and PDE2-overexpressing strains to these four antifungals, repressed the hyphal and biofilm formation of the strains, and decreased the intracellular cAMP level in the biofilms (all p < 0.05) compared to the untreated controls. In addition, farnesol decreased the expression of the gene CYR1 and the protein CYR1 in biofilms of the CYR1-overexpressing strain (all p < 0.05) but increased the expression of the gene PDE2 and the protein PDE2 in biofilms of the PDE2-overexpressing strain (all p < 0.01). CONCLUSIONS: The results indicate that CYR1 and PDE2 regulate the resistance of C. albicans biofilms to antifungals. Farnesol suppresses the resistance of C. albicans biofilms to antifungals by regulating the expression of the gene CYR1 and PDE2, while PDE2 regulation was subordinate to CYR1 regulation.


Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 2/metabolismo , Farmacorresistência Fúngica , Farneseno Álcool/farmacologia , Proteínas Fúngicas/metabolismo , Candida albicans/genética , Candida albicans/fisiologia , Caspofungina/farmacologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 2/genética , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Hifas/efeitos dos fármacos , Hifas/genética , Hifas/metabolismo , Terbinafina/farmacologia
18.
J Org Chem ; 79(3): 1449-53, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24467414

RESUMO

A novel CuO-catalyzed coupling reaction of arylhydrazines with trialkyl phosphites to afford arylphosphonates is described. The reaction proceeded at 80 °C in air without external reductants, oxidants, and ligands.


Assuntos
Cobre/química , Hidrazinas/química , Compostos Organofosforados/química , Compostos Organofosforados/síntese química , Oxidantes/química , Fosfitos/química , Catálise , Ligantes
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