ABSTRACT
BACKGROUND: It is generally known that PI3K/Akt/mTOR, MAPK, Jak/Stat, NF-κB and Notch signaling pathways play important roles in cell proliferation and differentiation, gene transcription, and immune inflammation. Hypoxia inducible factor-1α (HIF-1α) plays a crucial role in mediating the hypoxia signaling pathway and acts as a core factor in the hypoxic reaction process. OBJECTIVE: To summarize the relationship between HIF-1α and hypoxia signaling pathways, providing new ideas for the research and treatment of altitude diseases. METHODS: English literatures published during 2000-2019 were retrieved from PubMed and Medline. Chinese literatures published during 2011-2019 were retrieved from CNKI and WanFang databases. Search terms were “hypoxia inducible factor 1α, signal pathway” in English and Chinese, respectively. RESULTS AND CONCLUSION: During the occurrence of hypoxic-related diseases (inflammation, tumor, cardiovascular and cerebrovascular diseases) and altitude disease, the expression levels of HIF-1 and the key factors of these signaling pathways can change to varying degrees. HIF-1 is closely related to these signaling pathway under the hypoxic conditions, regulates molecular expression in these signaling pathways, or are regulated by these signaling pathways to increase or decrease, in response to the changes in the body under hypoxia conditions.
ABSTRACT
In order to brought S-naproxen into small intestine, an optically pure [S]-naproxen starch ester was produced by lipase through enantio-selective trans-esterification of racemic naproxen methyl ester with pretreatment starch in solvent system. With carefully selection of the reaction medium [isooctane], lipase [Carica Papaya Lipase, CPL] and the reaction mode [intermittent opening], a high conversion rate [48.6%] and enantiomeric excess of product [99.6%] was obtained. The slow release macromolecular [S]-Naproxen had been synthesized to improve the efficacy of racemic naproxen and overcome its side effects. The enanitomeric ratio of CPL [E=52.5] was higher than CRL [E=22] and greatly influenced by the byproduct methyl alcohol. The intermittent opening reaction mode was the effective way to remove the inhibition of methyl alcohol and to improve the enantio-selectivity of CPL. S-naproxen starch was confirmed by HPLC and [1]H NMR. This method may also apply to preparation the other optically pure 2-phenylpropionic acid derivatives. S-naproxen starch was a new optically pure derivatives possessing emulsifying and slow release properties would be widely applied to the food, pharmaceutical and biomedical industries
ABSTRACT
Methanotrophs can catalyze hydroxylate of methane and some hydrocarbon. Which play an important role in mitigating global warming and have also potential significance for industrial applications or bioremediation. A high activity of hydroxylase, a crucial component in sMMO, from Methylosinus trichosporium IMV 3011 has been purified to homologues by using chromatographic techniques. The molecular weight of the hydroxylase determined by gel filtration is 201.3 kD, and SDS-PAGE showed that hydroxylase consists of three subunits(alpha beta gamma) with molecular weights of 58kD, 36kD and 23kD respectively, drawing a comparison both methods indicated that the hydroxylase is a homodimer with an (alpha beta gamma)2 configuration. Purified hydroxylase has a pI at 5.2 judged by thin layer isoelectric focusing. The purified hydroxylase contains 3.02 mol of iron per mol of protein. The stability pH for the hydroxylase in solution is 5.8-8.0 and the stability temperature is below 35 degrees C. The cells form show a long, bent, and rod-shaped with even surface observed by scanning electron microscopy.
Subject(s)
Chemical Phenomena , Enzyme Stability , Hydrogen-Ion Concentration , Iron , Metabolism , Methylosinus trichosporium , Microscopy, Electron , Oxygenases , Chemistry , Metabolism , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet , TemperatureABSTRACT
Using a fluidized bed as immobilization system, mixed culture methanotrophic attached-films were developed on diatomite particles. The Methane Monooxygenase (MMO) activity was found to increase obviously as soon as the lag phase ended. Greater than 90% of the MMO activity in the bed was attached. Biofilm concentration of 3.3-3.7 mg dry weight cell/g DS was observed. Batch experiments were performed to explore the possibility of producing epoxypropane by a cooxidation process. The effect of methane on the oxidation of propene to epoxypropane and the effect of propene on the growth of methanotroph were also studied. In continuous experiments, optimum mixed gaseous substrates (methane: 35%; propene: 20%; oxygen: 45%) were continuously circulated through the fluidized bed reactor to remove product. Initial epoxypropane productivity was 110-150 mumol/d. The bioreactor operated continuously for 25 d without obvious loss of epoxypropane productivity.