In this case study, we designed a farnesyl pyrophosphate (FPP) biosynthetic network using hybrid functional Petri net with extension (HFPNe) which is derived from traditional Petri net theory and allows easy modeling with graphical approach of various types of entities in the networks together. Our main objective is to improve the production of FPP in yeast, which is further converted to amorphadiene (AD), a precursor of artemisinin (antimalarial drug). Natively, mevalonate (MEV) pathway is present in yeast. Methyl erythritol phosphate pathways (MEP) are present only in higher plant plastids and eubacteria, but not present in yeast. IPP and DAMP are common isomeric intermediate in these two pathways, which immediately yields FPP. By integrating these two pathways in yeast, we augmented the FPP synthesis approximately two folds higher (431.16 U/pt) than in MEV pathway alone (259.91 U/pt) by using HFPNe technique. Further enhanced FPP levels converted to AD by amorphadiene synthase gene yielding 436.5 U/pt of AD which approximately two folds higher compared to the AD (258.5 U/pt) synthesized by MEV pathway exclusively. Simulation and validation processes performed using these models are reliable with identified biological information and data. 相似文献
A series of {(9,9‐dioctylfluorene)0.7?x‐(dibenzothiophene‐S,S‐dioxide)0.3‐[4,7‐bis(2‐thienyl)‐2,1,3‐benzothiadiazole]x} (PFS30‐TBTx), where x represents the minor percentage of the red emitter 4,7‐bis(2‐thienyl)‐2,1,3‐benzothiadiazole (TBT) randomly incorporated into the copolymer backbone, is investigated in order to follow the energy transfer from PFS30 to TBT moieties. The emission of the donor poly[(9,9‐dioctylfluorene)0.7‐(dibenzothiophene‐S,S‐dioxide)0.3 identified by PFS30 and peaking at 450 nm, is clearly quenched by the presence of the red TBT chromophore emitting at 612 nm, with an isoemissive point observed when the spectra are collected as a function of temperature. A plot of the ratio between the TBT and PFS30 emissions as a function of the reciprocal of temperature gives a clear linear trend between 290 and 200 K, with an activation energy of 20 meV and showing a turn over to a non‐activated regime below 200 K. Picosecond time‐resolved fluorescence decays collected at the PFS30 and TBT emission wavelengths, show a decay of the PFS30 emission and a fast build‐in, followed by a decay, of the TBT emission, confirming that the population of the TBT excited state occurs during the PFS30 lifetime(~600 ps). The population of the TBT excited state occurs on a time regime around 150 ps at 290 K, showing an energy barrier of 20 meV that turns over to a non‐activated regime below 200 K in clear agreement with the steady‐state data. The origin of the activation barrier is attributed to the presence of physical and energetic disorder, affected by fast thermal fluctuations that dynamically change the energy landscape and control the exciton migration through the polymer density of states.相似文献
Random copolymers of poly(9,9‐di‐n‐octylfluorene) (PF8) incorporating 0, 8, 12, 15, and 20% dibenzothiophene (DBT), and copolymers with 2, 5, 8, 12, and 15% dibenzothiophene‐S,S‐dioxide (S‐unit) were synthesised. Absorption and emission spectra of thin films indicate that the DBT system shows a linear decrease of toluene vapour induced β phase with increasing DBT content to a 20% cutoff, whilst in the S‐unit copolymers the β phase is present up to 12% co‐monomer content, and at 15% the characteristic absorption peak is absent or masked. These results demonstrate the limits, in thin films, at which the β phase can be formed in widely used PF8 copolymer systems for device applications and clearly show that it is practical to use copolymers having electron or hole transport units in the polyfluorene backbone and still be able to form efficient β phase emission sites.