Publications by authors named "Guo-Qing Ying"
The clinical use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) is limited by its short serum half-life. In this study, a long-acting strategy for site-specific modification of rhG-CSF with 1-pentadecyl-1H-pyrrole-2,5-dione (C15 fatty chain-maleimide, C15-MAL) was studied in mixed DMSO-aqueous solutions. The factors influencing the conjugation reaction were investigated and optimized, and a high yield of the desired product (C15-rhG-CSF) was achieved.
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- * A new process using a salting-out extraction system (SOES) was developed, optimizing a blend of ethanol and phosphate to effectively separate and purify CA from fermentation broth.
- * The optimized SOES achieved a high recovery yield of 96.8% for CA and removed a significant percentage of cells and proteins, proving to be more efficient and cost-effective than traditional methods like membrane filtration or liquid-liquid extraction.
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- The report discusses the development of a new modified thrombin-binding aptamer (TBA) that incorporates anti-guanine bases and a loop-locked nucleic acid (LNA) to enhance binding to thrombin.
- Techniques like NMR, circular dichroic spectroscopy, and molecular modeling were used to analyze the three-dimensional structure of two G-quadruplexes formed by the modifications.
- The modifications not only improve the aptamer's stability and affinity for thrombin but also maintain strong inhibitory activity, suggesting that LNA modifications significantly enhance the aptamer's properties.
Construction and application of an electrochemical biosensor based on an endotoxin aptamer.
Biotechnol Appl Biochem
May 2018
An electrochemical biosensor that used an aptamer as a biological element was constructed to detect endotoxin. Biolayer interferometry was used to obtain the affinity constant of an aptamer for lipopolysaccharide, which had an equilibrium dissociation constant of 22.9 nM.
View Article and Find Full Text PDFObjectives: To select aptamers for endotoxin separation from a 75-nucleotide single-stranded DNA random library using systematic evolution of ligands by exponential enrichment.
Results: After 15 rounds of selection, the final pool of aptamers was specific to endotoxin. Structural analysis of aptamers that appeared more than once suggested that one aptamer can form a G-quartet structure.
Two water-soluble chitosan (WSC) derivatives of N-succinyl-chitosan (NSCS) and N,O-succinyl-chitosan (NOSCS) with a degree of substitution (DS) that ranged form 0.28 to 0.61 were selectively synthesized by varying the molar ration of succinic anhydride and chitosan.
View Article and Find Full Text PDFConditions were studied in the biosynthesis of cytidine 5'-triphosphate (CTP) from cytidine 5'-monophosphate (CMP). A 201 x 7 anion ion-exchange resin was applied for the separation of CTP from CMP. Adsorption isotherm and elution conditions (eluant, eluant concentration, flow rate, sample volume loaded) were investigated.
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