RESUMO
Engineering microorganisms for production of fuels and chemicals often requires major re-programming of metabolism to ensure high flux toward the product of interest. This is challenging, as millions of years of evolution have resulted in establishment of tight regulation of metabolism for optimal growth in the organism's natural habitat. Here, we show through metabolic engineering that it is possible to alter the metabolism of Saccharomyces cerevisiae from traditional ethanol fermentation to a pure lipogenesis metabolism, resulting in high-level production of free fatty acids. Through metabolic engineering and process design, we altered subcellular metabolic trafficking, fine-tuned NADPH and ATP supply, and decreased carbon flux to biomass, enabling production of 33.4 g/L extracellular free fatty acids. We further demonstrate that lipogenesis metabolism can replace ethanol fermentation by deletion of pyruvate decarboxylase enzymes followed by adaptive laboratory evolution. Genome sequencing of evolved strains showed that pyruvate kinase mutations were essential for this phenotype.
Assuntos
Ácidos Graxos não Esterificados/biossíntese , Engenharia Metabólica , Saccharomyces cerevisiae/metabolismo , Acetilcoenzima A/metabolismo , Glucose/metabolismo , Glicólise , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Lipogênese , NADP/metabolismo , Via de Pentose Fosfato/genética , Piruvato Quinase/genética , Piruvato Quinase/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
Groundwater is one of the chief water sources for agricultural activities in an aggregation of coal mines surrounded by agricultural areas in the Huaibei Plain. However, there have been few reports on whether mining-affected groundwater can be adopted for agricultural irrigation. We attempted to address this question through collecting 71 shallow groundwater samples from 12 coal mining locations. The Piper trilinear chart, the Gibbs diagram, the proportional coefficient of major ions, and principal component analysis were examined to characterize the source, origin, and formation process of groundwater chemical composition. The suitability for agricultural irrigation was evaluated by a final zonation map that establishes a comprehensive weighting model based on analytic hierarchy process and criteria importance though the intercriteria correlation (AHP-CRITIC). The results revealed that the groundwater was classified as marginally alkaline water with a predominant cation of HCO3- and anion of Na+. Total hardness, total dissolved solids, sulfate (SO42-), sodium (Na+), and fluoride (F-) were the primary ions that exceeded the standard. The results also indicated that the dominant hydrochemical facies were Ca-HCO3 and Na-Cl. The dissolution of carbonate, silicate, sulfate minerals, along with cation exchange, were the main natural drivers controlling the hydrogeochemical process of groundwater. The zonation map suggested that 43.17%, 18.85%, and 37.98% of the study area were high, mediate, and low suitability zones, respectively. These results from this study can support policymakers for better managing groundwater associated with a concentration of underground coal mines.
Assuntos
Minas de Carvão , Monitoramento Ambiental , Água Subterrânea , Poluentes Químicos da Água , Água Subterrânea/química , China , Poluentes Químicos da Água/análise , AgriculturaRESUMO
(2S)-Naringenin is a key precursor for biosynthesis of various high-value flavonoids and possesses a variety of nutritional and pharmaceutical properties on human health. Systematic optimization approaches have been employed to improve (2S)-naringenin production in different microbial hosts. However, very few studies have focused on the spatiotemporal distribution of (2S)-naringenin and the related pathway intermediate p-coumaric acid, which is an important factor for efficient production. Here, we first optimized the (2S)-naringenin biosynthetic pathway by alleviating the bottleneck downstream of p-coumaric acid and increasing malonyl-CoA supply, which improved (2S)-naringenin production but significant accumulation of p-coumaric acid still existed extracellularly. We thus established a dual dynamic control system through combining a malonyl-CoA biosensor regulator and an RNAi strategy, to autonomously control the synthesis of p-coumaric acid with the supply of malonyl-CoA. Furthermore, screening potential transporters led to identification of Pdr12 for improved (2S)-naringenin production and reduced accumulation of p-coumaric acid. Finally, a titer of 2.05 g/L (2S)-naringenin with negligible accumulation of p-coumaric acid was achieved in a fed batch fermentation. Our work highlights the importance of systematic control of pathway intermediates for efficient microbial production of plant natural products.
Assuntos
Flavanonas , Saccharomyces cerevisiae , Humanos , Ácidos Cumáricos , Malonil Coenzima A/genéticaRESUMO
Phospholipids, the most abundant membrane lipid components, are crucial in maintaining membrane structures and homeostasis for biofunctions. As a structurally diverse and tightly regulated system involved in multiple organelles, phospholipid metabolism is complicated to manipulate. Thus, repurposing phospholipids for lipid-derived chemical production remains unexplored. Herein, we develop a Saccharomyces cerevisiae platform for de novo production of oleoylethanolamide, a phospholipid derivative with promising pharmacological applications in ameliorating lipid dysfunction and neurobehavioral symptoms. Through deregulation of phospholipid metabolism, screening of biosynthetic enzymes, engineering of subcellular trafficking and process optimization, we could produce oleoylethanolamide at a titer of 8,115.7 µg l-1 and a yield on glucose of 405.8 µg g-1. Our work provides a proof-of-concept study for systemically repurposing phospholipid metabolism for conversion towards value-added biological chemicals, and this multi-faceted framework may shed light on tailoring phospholipid metabolism in other microbial hosts.
Assuntos
Endocanabinoides/biossíntese , Engenharia Metabólica/métodos , Ácidos Oleicos/biossíntese , Fosfolipídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Acil Coenzima A/genética , CDPdiacilglicerol-Serina O-Fosfatidiltransferase/genética , CDPdiacilglicerol-Serina O-Fosfatidiltransferase/metabolismo , Coenzima A Ligases/genética , Endocanabinoides/genética , Enzimas/genética , Enzimas/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Lisofosfolipase/genética , Lisofosfolipase/metabolismo , Microrganismos Geneticamente Modificados , Monoacilglicerol Lipases/genética , Monoacilglicerol Lipases/metabolismo , Ácidos Oleicos/genética , Proteínas Periplásmicas/genética , Proteínas Periplásmicas/metabolismo , Fosfolipídeos/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
The cellular machinery that supports protein synthesis and secretion lies at the foundation of cell factory-centered protein production. Due to the complexity of such cellular machinery, the challenge in generating a superior cell factory is to fully exploit the production potential by finding beneficial targets for optimized strains, which ideally could be used for improved secretion of other proteins. We focused on an approach in the yeast Saccharomyces cerevisiae that allows for attenuation of gene expression, using RNAi combined with high-throughput microfluidic single-cell screening for cells with improved protein secretion. Using direct experimental validation or enrichment analysis-assisted characterization of systematically introduced RNAi perturbations, we could identify targets that improve protein secretion. We found that genes with functions in cellular metabolism (YDC1, AAD4, ADE8, and SDH1), protein modification and degradation (VPS73, KTR2, CNL1, and SSA1), and cell cycle (CDC39), can all impact recombinant protein production when expressed at differentially down-regulated levels. By establishing a workflow that incorporates Cas9-mediated recombineering, we demonstrated how we could tune the expression of the identified gene targets for further improved protein production for specific proteins. Our findings offer a high throughput and semirational platform design, which will improve not only the production of a desired protein but even more importantly, shed additional light on connections between protein production and other cellular processes.
Assuntos
Interferência de RNA , Proteínas Recombinantes/biossíntese , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Genoma Fúngico , Microfluídica , Proteínas Recombinantes/genética , Recombinação Genética , Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
Detection of cell-free DNA (cfDNA) has an impact on DNA analysis in liquid biopsies. However, current strategies to detect cfDNA have limitations that should be overcome, such as having low sensitivity and requiring much time and a specialized instrument. Thus, non-invasive and rapid detection tools are needed for disease prevention and early-stage treatment. Here we developed a device having a microheater integrated with zinc oxide nanowires (microheater-ZnO-NWs) to detect target single-stranded DNAs (ssDNAs) based on DNA probe hybridization. We confirmed experimentally that our device realizedin-situannealed DNA probes by which we subsequently detected target ssDNAs. We envision that this device can be utilized for fundamental studies related to nanobiodevice-based DNA detection.
Assuntos
Técnicas Biossensoriais , Ácidos Nucleicos Livres/análise , DNA de Cadeia Simples/análise , Dispositivos Lab-On-A-Chip , Nanofios/química , Óxido de Zinco/química , Sondas de DNA/química , Humanos , Limite de Detecção , Biópsia Líquida/métodos , Hibridização de Ácido Nucleico/métodosRESUMO
CONTEXT: The petroleum ether extract (PET) of Amygdalus mongolica (Maxim.) Ricker (Rosaceae) has an ameliorative effect on renal fibrosis (RF). OBJECTIVE: To evaluate the antifibrotic effects of A. mongolica seeds PET on RF by serum metabolomics, biochemical and histopathological analyses. MATERIALS AND METHODS: Sixty male Sprague-Dawley rats were randomly divided into the sham-operated, RF model, benazepril hydrochloride-treated model (1.5 mg/kg) and PET-treated (1.75, 1.25, 0.75 g/kg) groups, and the respective drugs were administered intragastrically for 21 days. Biochemical indicators including BUN, Scr, HYP, SOD, and MDA were measured. Haematoxylin and eosin and Masson staining were used for histological examination. The serum metabolomic profiles were determined by UPLC-Q-TOF/MS and metabolism network analysis. Acute toxicity test was performed to validate biosafety. RESULTS: The PET LD50 was >23.9 g/kg in rats. PET significantly alleviated fibrosis by reducing the levels of Scr (from 34.02 to 32.02), HYP (from 403.67 to 303.17) and MDA (from 1.84 to 1.73), and increasing that of SOD (from 256.42 to 271.85). Metabolomic profiling identified 10 potential biomarkers, of which three key markers were significantly associated with RF-related pathways including phenylalanine, tyrosine and tryptophan biosynthesis, amino sugar and nucleotide sugar metabolism and tyrosine metabolism. In addition, three key biomarkers were restored to baseline levels following PET treatment, with the medium dose showing optimal effect. CONCLUSIONS: These findings revealed the mechanism of A. mongolica PET antifibrotic effects for RF rats on metabolic activity and provided the experimental basis for the clinical application.
Assuntos
Alcanos , Antifibróticos/uso terapêutico , Nefropatias/tratamento farmacológico , Metabolômica/métodos , Extratos Vegetais/uso terapêutico , Rosaceae , Animais , Antifibróticos/isolamento & purificação , Fibrose , Nefropatias/metabolismo , Nefropatias/patologia , Masculino , Extratos Vegetais/isolamento & purificação , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: To determine the effect of large genomic region deletion in a Saccharomyces cerevisiae strain on tyrosine yield and to identify new genetic modification targets through transcriptome analysis. RESULTS: TAL was used to produce p-coumaric acid (p-CA) from tyrosine to quantity tyrosine yield. S. cerevisiae mutant strain NK14 with deletion of a 23.8 kb genomic region was identified to have p-CA production of 10.3 mg L- 1, while the wild-type strain BY4741 had p-CA production of 1.06 mg L- 1. Analysis of growth patterns and stress tolerance showed that the deletion did not affect the growth phenotype of NK14. Transcriptome analysis suggested that, compared to BY4741, genes related to glycolysis (ENO2, TKL1) and the tyrosine pathway (ARO1, ARO2, ARO4, ARO7, TYR1) were upregulated in NK14 at different levels. Besides genes related to the tyrosine biosynthetic pathway, amino acid transporters (AVT6, VBA5, THI72) and transcription factor (ARO80) also showed changes in transcription levels. CONCLUSIONS: We developed a strain with improved tyrosine yield and identified new genetic modification candidates for tyrosine production.
Assuntos
Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Deleção de Sequência , Transcriptoma , Tirosina/biossíntese , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/biossíntese , Proteínas de Saccharomyces cerevisiae/genética , Tirosina/genéticaRESUMO
1. To investigate Genkwa Flos hepatotoxicity, a cell metabolomics strategy combined with serum pharmacology was performed on human HL-7702 liver cells in this study. 2. Firstly, cell viability and biochemical indicators were determined and the cell morphology was observed to confirm the cell injury and develop a cell hepatotoxicity model. Then, with the help of cell metabolomics based on UPLC-MS, the Genkwa Flos group samples were completely separated from the blank group samples in the score plots and seven upregulated as well as two down-regulated putative biomarkers in the loading plot were identified and confirmed. Besides, two signal molecules and four enzymes involved in biosynthesis pathway of lysophosphatidylcholine and the sphingosine kinase/sphingosine-1-phosphate pathway were determined to investigate the relationship between Genkwa Flos hepatotoxicity and these two classic pathways. Finally, the metabolic pathways related to specific biomarkers and two classic metabolic pathways were analyzed to explain the possible mechanism of Genkwa Flos hepatotoxicity. 3. Based on the results, lipid peroxidation and oxidative stress, phospholipase A2/lysophosphatidylcholine pathway, the disturbance of sphingosine-1-phosphate metabolic profile centered on sphingosine kinase/sphingosine-1-phosphate pathway and fatty acid metabolism might be critical participators in the progression of liver injury induced by Genkwa Flos.
Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Fígado/efeitos dos fármacos , Animais , Células Cultivadas , Daphne/química , Medicamentos de Ervas Chinesas/efeitos adversos , Humanos , Fígado/metabolismo , Masculino , Redes e Vias Metabólicas , Metabolômica , Estresse Oxidativo , Ratos Sprague-Dawley , Organismos Livres de Patógenos EspecíficosRESUMO
Context: Terrestrosin D (TED), from Tribulus terrestris L. (Zygophyllaceae), exhibits anti-tumour and anti-inflammatory activities. However, its effects on bleomycin (BLM)-induced pulmonary inflammation and the subsequent fibrotic changes remain unclear. Objective: To examine the anti-inflammatory and anti-fibrotic effects of TED against BLM in murine pulmonary tissues. Materials and methods: Male SPF mice received saline (control), TED (10 mg/kg), BLM (2.5 mg/kg), or BLM (2.5 mg/kg) + TED (10 mg/kg) group. BLM was administered as a single intranasal inoculation, and TED was intraperitoneally administered once daily. After 2 and 6 weeks of treatment, cell number and differentiation (Giemsa staining) and TNF-α, IL-6, IL-8, TGF-ß1, and PDGF-AB levels (ELISA) were determined in the bronchoalveolar lavage fluid (BALF). Hydroxyproline (Hyp) content in the left pulmonary tissue was also determined (ELISA). The right pulmonary tissue was H&E-stained and assessed for the severity of pulmonary fibrosis using the Ashcroft scoring method. Compared with the BLM group, TED decreased inflammatory cell infiltration; number of macrophages (p < 0.05), neutrophils (p < 0.05), lymphocytes (p < 0.05); percentage of macrophages in the monocyte-macrophage system (p < 0.05), and levels of TNF-α (p < 0.01), IL-6 (p < 0.01), IL-8 (p < 0.05), TGF-ß1 (p < 0.05), and PDGF-AB (p < 0.05) in the BALF. TED also reduced Hyp content (p < 0.05) in the pulmonary tissue and attenuated the BLM-induced deterioration in lung histopathology. Discussion and conclusions: TED can inhibit BLM-induced inflammation and fibrosis in the lungs of mice, which may be related to reduced inflammatory and fibrotic markers. These results could be further tested in humans through clinical studies.
Assuntos
Anti-Inflamatórios/farmacologia , Inflamação/tratamento farmacológico , Fibrose Pulmonar/tratamento farmacológico , Saponinas/farmacologia , Tribulus/química , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/uso terapêutico , Bleomicina , Líquido da Lavagem Broncoalveolar , Modelos Animais de Doenças , Inflamação/patologia , Masculino , Camundongos , Fibrose Pulmonar/patologia , Saponinas/isolamento & purificação , Saponinas/uso terapêuticoRESUMO
As a traditional ethanol-producing microorganism, Saccharomyces cerevisiae is an ideal host for consolidated bioprocessing. However, expression of heterologous cellulase increases the metabolic burden in yeast, which results in low cellulase activity and poor cellulose degradation efficiency. In this study, cellulase-expressing yeast strains that could efficiently degrade different cellulosic substrates were created by optimizing cellulase ratios through a POT1-mediated δ-integration strategy. Metabolic engineering strategies, including optimization of codon usage, promoter and signal peptide, were also included in this system. We also confirmed that heterologous cellulase expression in cellulosic yeast induced the unfolded protein response. To enhance protein folding capacity, the endoplasmic reticulum chaperone protein BiP and the disulfide isomerase Pdi1p were overexpressed, and the Golgi membrane protein Ca2+/Mn2+ ATPase Pmr1p was disrupted to decrease the glycosylation of cellulase. The resultant strain, SK18-3, could produce 5.4 g L-1 ethanol with carboxymethyl-cellulose. Strain SK12-50 achieved 4.7 g L-1 ethanol production with phosphoric acid swollen cellulose hydrolysis. When Avicel was used as the substrate, 3.8 g L-1 ethanol (75% of the theoretical maximum yield) was produced in SK13-34. This work will significantly increase our knowledge of how to engineer optimal yeast strains for biofuel production from cellulosic biomass.
Assuntos
Celulase/genética , Celulase/metabolismo , Celulose/metabolismo , Etanol/metabolismo , Engenharia Metabólica/métodos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Códon , Expressão Gênica , Regiões Promotoras Genéticas , Sinais Direcionadores de Proteínas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
Heavy metal accumulation and potential releases from loose deposits in drinking water distribution system (DWDS) can have critical impacts on drinking water safety, but the associated risks have not been sufficiently evaluated. In this work, the potential biological toxicity of heavy metals in loose deposits was calculated based on consensus-based sediment quality guidelines, and the effects of some of the main water quality parameters, such as the pH and bicarbonate and phosphate content, on the release behaviors of pre-accumulated heavy metals were investigated. The results showed that heavy metals (Cu, As, Cr, Pb, and Cd) significantly accumulated in all the samples, but the contents of the heavy metals were multiple magnitudes lower than the Fe and Mn contents. The potential biotoxicity of As and Cu was relatively high, but the biotoxicity of Cd was negligible. The water quality can significantly influence the release of heavy metals from loose deposits. As the pH increased from 7.0 to 9.0, the release of As and Cr obviously increased. The release of As, Cu, Pb, and Cr also accelerated with the addition of phosphate (from 1 to 5 mg/L). In contrast to the trends for the pH and phosphate, variations in the bicarbonate content did not have a significant influence on the release of As and Cr. The release ratios of heavy metals in the samples were very low, and there was not a correlation between the release rate of the heavy metals in the loose deposits and their potential biotoxicity.
Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Água Potável/química , Sedimentos Geológicos/química , Qualidade da ÁguaRESUMO
In biotechnological industry, increased expression cassette stability and copy number serve as important means of maintaining consistently high production levels of heterologous proteins in Saccharomyces cerevisiae. In this study, we combined δ sequences for site-specific integration with TPI1 gene from Schizosaccharomyces pombe (POT1) as a selection marker to realize high-copy integration and stable expression of heterologous proteins in S. cerevisiae. With the newly developed POT1 platform, a 32-copy integration of enhanced green fluorescent protein (EGFP) expression cassette was obtained in a single round and was stably maintained after 100 generations of growth in a rich complex medium. Talaromyces emersonii cellobiohydrolase I gene was synthesized with S. cerevisiae codon bias and expressed under the control of TPI1 promoter and terminator via POT1-mediated δ-integration; the highest specific activity yielded 238 mU g-1 of dry cell weight when p-nitrophenyl-ß-D-cellobioside was used as substrate, whereas the highest activity in cellulose hydrolysis reached 67% Avicel conversion. POT1-mediated δ-integration produces high protein levels over a wide dynamic range and enables broad applications in metabolic engineering and synthetic biology.
Assuntos
Dosagem de Genes , Expressão Gênica , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Celulose 1,4-beta-Celobiosidase/análise , Celulose 1,4-beta-Celobiosidase/genética , Eurotiales/enzimologia , Eurotiales/genética , Genes Reporter , Instabilidade Genômica , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Proteínas Recombinantes/biossíntese , Recombinação Genética , Schizosaccharomyces/enzimologia , Schizosaccharomyces/genéticaRESUMO
The seeds of Amygdalus mongolica contain various constituents including flavonoids and vitamin E, which are known to exert antioxidant effects. However, the safety of the oil extract of this compound is not fully known. The aim of this study was to determine the physicochemical properties of A. mongolica oil, identify the constituents and subsequently assess the effectiveness of utilizing this seed extract in hyperlipidemia as an antioxidant agent. In particular, the toxicity and safety of A. mongolica oil were examined with emphasis on effects on blood lipids level and serum lipid peroxidation using a hyperlipidemia rat model. Treatment with 20 ml/kg A. mongolica oil produced no apparent adverse effects after 14 days in normal female and male rats. A dose of 2.5-10 ml/kg A. mongolica oil administered to hyperlipidemic male rats significantly decreased serum total cholesterol (TC), low-density lipoprotein-C (LDL-C), malondialdehyde (MDA), total cholesterol high-density lipoprotein-C (TC/HDL-C), LDL-C/HDL-C, and atherosclerosis index(AI). In contrast, glutathione (GSH) levels and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly increased. Data demonstrated that A. mongolica oil may be utilized in conditions of hyperlipidemia due to its antioxidant effects.
Assuntos
Hiperlipidemias/tratamento farmacológico , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Prunus/química , Ratos , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Ativação Enzimática/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Lipídeos/sangue , Masculino , Oxirredutases/genética , Oxirredutases/metabolismo , Distribuição Aleatória , Ratos WistarRESUMO
Trichosanthin (TCS), isolated from the root tuber of Trichosantheskirilowii, a well-known traditional Chinese medicinal plant, belonging to the Cucurbitaceae family, was found to exhibit numerous biological and pharmacological activities including anti-inflammatory. However, the effects of TCS on arterial injury induced neointimal hyperplasia and inflammatory cell infiltration remains poorly understood. The aim of study was to examine the effectiveness of TCS on arterial injury-mediated inflammatory processes and underlying mechanisms. A balloon-injured carotid artery induced injury in vivo in rats was established as a model of vascular injury. After 1 day TCS at 20, 40, or 80 mg/kg/day was administered intraperitoneally, daily for 14 days. Subsequently, the carotid artery was excised and taken for immunohistochemical staining. Data showed that TCS significantly dose-dependently reduced balloon injury-induced neointima formation in the carotid artery model rat, accompanied by markedly decreased positive expression percentage proliferating cell nuclear antigen (PCNA). In the in vitro study vascular smooth muscle cells (VSMC) were cultured, proliferation stimulated with platelet-derived growth factor-BB (PDGF-BB) (20 ng/ml) and TCS at 1, 2, or 4 µM added. Data demonstrated that TCS inhibited proliferation and cell cycle progression of VSMC induced by PDGF-BB. Further, TCS significantly lowered mRNA expression of cyclinD1, cyclinE1, and c-fos, and protein expression levels of Akt1, Akt2, and mitogen-activated protein kinase MAPK (ERK1) signaling pathway mediated by PDGF-BB. These findings indicate that TCS inhibits vascular neointimal hyperplasia induced by vascular injury in rats by suppression of VSMC proliferation and migration, which may involve inhibition of Akt/MAPK/ERK signal pathway.
Assuntos
Hiperplasia/tratamento farmacológico , Neointima/tratamento farmacológico , Tricosantina/farmacologia , Tricosantina/uso terapêutico , Lesões do Sistema Vascular/tratamento farmacológico , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Catéteres/efeitos adversos , Hiperplasia/etiologia , Masculino , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Lesões do Sistema Vascular/etiologiaRESUMO
OBJECTIVE: To identify new enzymatic bottlenecks of L-tyrosine pathway for further improving the production of L-tyrosine and its derivatives. RESULT: When ARO4 and ARO7 were deregulated by their feedback resistant derivatives in the host strains, the ARO2 and TYR1 genes, coding for chorismate synthase and prephenate dehydrogenase were further identified as new important rate-limiting steps. The yield of p-coumaric acid in the feedback-resistant strain overexpressing ARO2 or TYR1, was significantly increased from 6.4 to 16.2 and 15.3 mg l-1, respectively. Subsequently, we improved the strain by combinatorial engineering of pathway genes increasing the yield of p-coumaric acid by 12.5-fold (from 1.7 to 21.3 mg l-1) compared with the wild-type strain. Batch cultivations revealed that p-coumaric acid production was correlated with cell growth, and the formation of by-product acetate of the best producer NK-M6 increased to 31.1 mM whereas only 19.1 mM acetate was accumulated by the wild-type strain. CONCLUSION: Combinatorial metabolic engineering provides a new strategy for further improvement of L-tyrosine or other metabolic biosynthesis pathways in S. cerevisiae.
Assuntos
Anti-Infecciosos/metabolismo , Fósforo-Oxigênio Liases/metabolismo , Prefenato Desidrogenase/metabolismo , Propionatos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Tirosina/metabolismo , Ácidos Cumáricos , Expressão Gênica , Engenharia Metabólica , Redes e Vias Metabólicas/genética , Fósforo-Oxigênio Liases/genética , Prefenato Desidrogenase/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
Research towards nucleic acid amplification technologies for detection of human papillomavirus (HPV) 16 E6/E7 mRNA was carried out in combination with microchip electrophoresis (MCE). The approaches of nucleic acid sequence based amplification (NASBA), one-step RT-PCR and two-step RT-PCR were successfully developed. NASBA was a simple enzymatic reaction, which directly amplified HPV16 mRNA by isothermal amplification, leaving out the complex and tedious operation. One-step RT-PCR simplified the amplification step, while two-step RT-PCR was more sensitive and less vulnerable to the interference. Furthermore, instead of gel electrophoresis, microchip electrophoresis (MCE) for RNA assay was employed to realize high-throughput and rapid analysis. Finally, the results show that PCR-based or NASBA-based mRNA tests are valuable for HPV mRNA assay, which can be potentially applied for clinical diagnosis and prognosis of cervical and other anogenital carcinoma.
Assuntos
Eletroforese em Microchip/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Proteínas Oncogênicas Virais/genética , Proteínas E7 de Papillomavirus/genética , Proteínas Repressoras/genética , Soluções Tampão , RNA Mensageiro/análise , RNA Mensageiro/genética , RNA Mensageiro/isolamento & purificaçãoRESUMO
The persistent and increasing levels of sulfate due to a variety of human activities over the last decades present a widely concerning environmental issue. Understanding the controlling factors of groundwater sulfate and predicting sulfate concentration is critical for governments or managers to provide information on groundwater protection. In this study, the integration of self-organizing map (SOM) approach and machine learning (ML) modeling offers the potential to determine the factors and predict sulfate concentrations in the Huaibei Plain, where groundwater is enriched with sulfate and the areas have complex hydrogeological conditions. The SOM calculation was used to illustrate groundwater hydrochemistry and analyze the correlations among the hydrochemical parameters. Three ML algorithms including random forest (RF), support vector machine (SVM), and back propagation neural network (BPNN) were adopted to predict sulfate levels in groundwater by using 501 groundwater samples and 8 predictor variables. The prediction performance was evaluated through statistical metrics (R2, MSE and MAE). Mine drainage mainly facilitated increase in groundwater SO42- while gypsum dissolution and pyrite oxidation were found another two potential sources. The major water chemistry type was Ca-HCO3. The dominant cation was Na+ while the dominant anion was HCO3-. There was an intuitive correlation between groundwater sulfate and total dissolved solids (TDS), Cl-, and Na+. By using input variables identified by the SOM method, the evaluation results of ML algorithms showed that the R2, MSE and MAE of RF, SVM, BPNN were 0.43-0.70, 0.16-0.49 and 0.25-0.44. Overall, BPNN showed the best prediction performance and had higher R2 values and lower error indices. TDS and Na+ had a high contribution to the prediction accuracy. These findings are crucial for developing groundwater protection and remediation policies, enabling more sustainable management.
RESUMO
Based on a specific zinc storage mechanism and excellent electronic conductivity, transition metal dichalcogenides, represented by vanadium diselenide, are widely used in aqueous zinc-ion battery (AZIB) energy storage systems. However, most vanadium diselenide cathode materials are presently limited by low specific capacity and poor cycling life. Herein, a simple hydrothermal process has been proposed for obtaining a vanadium diselenide cathode for an AZIB. The interaction of defects and crystal planes enhances zinc storage capacity and reduces the migration energy barrier. Moreover, abundant lamellar structure greatly increases reaction sites and alleviates volume expansion during the electrochemical process. Thus, the as-obtained vanadium diselenide AZIB exhibits an excellent reversible specific capacity of 377 mAh g-1 at 1 A g-1, and ultralong cycle stability of 291 mAh g-1 after 3200 cycles, with a nearly negligible capacity loss. This one-stone-for-two-birds strategy would be expected to be applied to large-scale synthesis of a high-performance zinc-ion battery cathode in the future.
RESUMO
The technology of sensor, pervasive computing, and intelligent information processing is widely used in Body Sensor Networks (BSNs), which are a branch of wireless sensor networks (WSNs). BSNs are playing an increasingly important role in the fields of medical treatment, social welfare and sports, and are changing the way humans use computers. Existing surveys have placed emphasis on the concept and architecture of BSNs, signal acquisition, context-aware sensing, and system technology, while this paper will focus on sensor, data fusion, and network communication. And we will introduce the research status of BSNs, the analysis of hotspots, and future development trends, the discussion of major challenges and technical problems facing currently. The typical research projects and practical application of BSNs are introduced as well. BSNs are progressing along the direction of multi-technology integration and intelligence. Although there are still many problems, the future of BSNs is fundamentally promising, profoundly changing the human-machine relationships and improving the quality of people's lives.