| 1. |
- Khademian, A., et al.
(författare)
-
Phytochemical analysis of Echinops macrophyllus Boiss & Hausskn
- 2023
-
Ingår i: Trends in Phytochemical Research. - : Islamic Azad University. - 2588-3623. ; 7:4, s. 246-252
-
Tidskriftsartikel (refereegranskat)abstract
- Echinops macrophyllus Boiss & Hausskn, also known as “Shekartighal kohgiluyeh” in Persian, is a prickly perennial herbaceous plant. Various species within the genus Echinops have traditionally been used as remedies for severe coughs, nervous attacks, and infectious diseases. This study aimed to isolate and elucidate the structures of the compounds found in the aerial parts of E. macrophyllus. The ethyl acetate extract from the aerial parts of the plant was fractionated using column chromatography. The structures of the isolated compounds were characterized using 1 H NMR,13C NMR,1H-1H COSY, HSQC-DEPT, HMBC and NOESY techniques. Phytochemical analysis of the plant resulted in the isolation of six compounds (1-6), including one triterpenoid (α-amyrin) (4), three sterols involving 3-O-[β-D-(6’-tetradecanoate)-glucopyranosyl]-β-sitosterol (6), β-sitosterol (3), and daucosterol (5) as well as two phenolic compounds, namely p-hydroxybenzoic acid (1) and ethyl-2-hydroxy-trans-cinamate (2), from this species for the first time. It is noteworthy that these compounds have previously been reported to exhibit various biological activities.
|
|
| 2. |
|
|
| 3. |
- Asadollahi, M. A., et al.
(författare)
-
Enhancement of Farnesyl Diphosphate Pool as Direct Precursor of Sesquiterpenes Through Metabolic Engineering of the Mevalonate Pathway in Saccharomyces cerevisiae
- 2010
-
Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 106:1, s. 86-96
-
Tidskriftsartikel (refereegranskat)abstract
- The mevalonate pathway in the yeast Saccharomyces cerevisiae was deregulated in order to enhance the intracellular pool of farnesyl diphosphate (FPP), the direct precursor for the biosynthesis of sesquiterpenes. Overexpression of the catalytic domain of HMG1, both from the genome and plasmid, resulted in higher production of cubebol, a plant originating sesquiterpene, and increased squalene accumulation. Down-regulation of ERG9 by replacing its native promoter with the regulatable MET3 promoter, enhanced cubebol titers but simultaneous overexpression of tHMG1 and repression of ERG9 did not further improve cubebol production. Furtheremore, the concentrations of squalene and ergosterol were measured in the engineered strains. Unexpectedly, significant accumulation of squalene and restoring the ergosterol biosynthesis were observed in the ERG9 repressed strains transformed with the plasmids harboring cubebol synthase gene. This could be explained by a toxicity effect of cubebol, possibly resulting in higher transcription levels for the genes under control of MET3 promoter, which could lead to accumulation of squalene and ergosterol. Biotechnol. Bioeng. 2010;106: 86-96. (C) 2010 Wiley Periodicals, Inc.
|
|
| 4. |
- Asadollahi, M. A., et al.
(författare)
-
Enhancing sesquiterpene production in Saccharomyces cerevisiae through in silico driven metabolic engineering
- 2009
-
Ingår i: Metabolic Engineering. - : Elsevier BV. - 1096-7176 .- 1096-7184. ; 11:6, s. 328-334
-
Tidskriftsartikel (refereegranskat)abstract
- A genome-scale metabolic model was used to identify new target genes for enhanced biosynthesis of sesquiterpenes in the yeast Saccharomyces cerevisiae. The effect of gene deletions on the flux distributions in the metabolic model of S. cerevisiae was assessed using Opt Gene as the modeling framework and minimization of metabolic adjustments (MOMA) as objective function. Deletion of NADPH-dependent glutamate dehydrogenase encoded by GDH1 was identified as the best target gene for the improvement of sesquiterpene biosynthesis in yeast. Deletion of this gene enhances the available NADPH in the cytosol for other NADPH requiring enzymes, including HMG-CoA reductase. However, since disruption of GDH1 impairs the ammonia utilization, simultaneous over-expression of the NADH-dependent glutamate dehydrogenase en coded by GDH2 was also considered in this study. Deletion of GDH1 led to an approximately 85% increase in the final cubebol titer. However, deletion of this gene also caused a significant decrease in the maximum specific growth rate. Over-expression of GDH2 did not show a further effect on the final cubebol titer but this alteration significantly improved the growth rate compared to the GDH1 deleted strain. (C) 2009 Elsevier Inc. All rights reserved.
|
|
| 5. |
|
|
| 6. |
- Maury, J., et al.
(författare)
-
Reconstruction of a bacterial isoprenoid biosynthetic pathway in Saccharomyces cerevisiae
- 2008
-
Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 582:29, s. 4032-4038
-
Tidskriftsartikel (refereegranskat)abstract
- A eukaryotic mevalonate pathway transferred and expressed in Escherichia coli, and a mammalian hydrocortisone biosynthetic pathway rebuilt in Saccharomyces cerevisiae are examples showing that transferring metabolic pathways from one organism to another can have a powerful impact on cell properties. In this study, we reconstructed the E. coli isoprenoid biosynthetic pathway in S. cerevisiae. Genes encoding the seven enzymatic steps of the pathway were cloned and expressed in S. cerevisiae. mRNA from the seven genes was detected, and the pathway was shown able to sustain growth of yeast in conditions of inhibition of its constitutive isoprenoid biosynthetic pathway. © 2008 Federation of European Biochemical Societies.
|
|
| 7. |
- Otero, José Manuel, 1979, et al.
(författare)
-
Whole genome sequencing of Saccharomyces cerevisiae: from genotype to phenotype for improved metabolic engineering applications
- 2010
-
Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 11:1, s. 723-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The need for rapid and efficient microbial cell factory design and construction are possible through the enabling technology, metabolic engineering, which is now being facilitated by systems biology approaches. Metabolic engineering is often complimented by directed evolution, where selective pressure is applied to a partially genetically engineered strain to confer a desirable phenotype. The exact genetic modification or resulting genotype that leads to the improved phenotype is often not identified or understood to enable further metabolic engineering.Results: In this work we performed whole genome high-throughput sequencing and annotation can be used to identify single nucleotide polymorphisms (SNPs) between Saccharomyces cerevisiae strains S288c and CEN.PK113-7D. The yeast strain S288c was the first eukaryote sequenced, serving as the reference genome for the Saccharomyces Genome Database, while CEN.PK113-7D is a preferred laboratory strain for industrial biotechnology research. A total of 13,787 high-quality SNPs were detected between both strains (reference strain: S288c). Considering only metabolic genes (782 of 5,596 annotated genes), a total of 219 metabolism specific SNPs are distributed across 158 metabolic genes, with 85 of the SNPs being nonsynonymous (e. g., encoding amino acid modifications). Amongst metabolic SNPs detected, there was pathway enrichment in the galactose uptake pathway (GAL1, GAL10) and ergosterol biosynthetic pathway (ERG8, ERG9). Physiological characterization confirmed a strong deficiency in galactose uptake and metabolism in S288c compared to CEN.PK113-7D, and similarly, ergosterol content in CEN.PK113-7D was significantly higher in both glucose and galactose supplemented cultivations compared to S288c. Furthermore, DNA microarray profiling of S288c and CEN.PK113-7D in both glucose and galactose batch cultures did not provide a clear hypothesis for major phenotypes observed, suggesting that genotype to phenotype correlations are manifested post-transcriptionally or post-translationally either through protein concentration and/or function.Conclusions: With an intensifying need for microbial cell factories that produce a wide array of target compounds, whole genome high-throughput sequencing and annotation for SNP detection can aid in better reducing and defining the metabolic landscape. This work demonstrates direct correlations between genotype and phenotype that provides clear and high-probability of success metabolic engineering targets. The genome sequence, annotation, and a SNP viewer of CEN.PK113-7D are deposited at http://www.sysbio.se/cenpk.
|
|
| 8. |
- Jorjani, E., et al.
(författare)
-
Prediction of coal response to froth flotation based on coal analysis using regression and artificial neural network
- 2009
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875. ; 22:11, s. 970-976
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, the combustible value (i.e. 100-Ash) and combustible recovery of coal flotation concentrate were predicted by regression and artificial neural network based on proximate and group macerals analysis. The regression method shows that the relationships between (a) ln (ash), volatile matter and moisture (b) ln (ash), ln (liptinite), fusinite and vitrinite with combustible value can achieve the correlation coefficients (R2) of 0.8 and 0.79, respectively. In addition, the input sets of (c) ash, volatile matter and moisture (d) ash, liptinite and fusinite can predict the combustible recovery with the correlation coefficients of 0.84 and 0.63, respectively. Feed-forward artificial neural network with 6-8-12-11-2-1 arrangement for moisture, ash and volatile matter input set was capable to estimate both combustible value and combustible recovery with correlation of 0.95. It was shown that the proposed neural network model could accurately reproduce all the effects of proximate and group macerals analysis on coal flotation system.
|
|
| 9. |
- Maury, J., et al.
(författare)
-
Metabolic engineering of isoprenoid production: Reconstruction of multistep heterologous pathways in tractable hosts
- 2013
-
Ingår i: Isoprenoid Synthesis in Plants and Microorganisms: New Concepts and Experimental Approaches. - New York, NY : Springer New York. - 9781461440635 ; , s. 73-89
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Isoprenoids represent a wide group of chemically active compounds that can find a wide range of applications as flavors, perfumes, vitamins, nutraceuticals, and pharmaceuticals. Many isoprenoids are naturally produced in very low quantities by plants, which make their use in broader perspectives difficult. Microbial production of plant-originating isoprenoids quickly appeared as an alternative of choice. Metabolic engineering methods were applied and proved successful to improve the supply of precursors to derive toward isoprenoid compounds of interest. Combinations between metabolic engineering and the flourishing field of synthetic biology have also been observed with researchers attempting to reconstruct and optimize complex biosynthetic pathways in well-characterized and tractable microbial hosts. In this chapter, we review recent metabolic engineering studies for isoprenoid production in yeast and try to show, through key examples, that the fields of synthetic biology and metabolic engineering can go hand in hand to establish microbial cell factories for isoprenoid production.
|
|
