pH-sensitive polymer-assisted refolding of urea-denatured fibroblast growth factor

A pH-responsive polymer Eudragit S-100 has been found to assist in correct folding of FGF-2 （fibroblast growth factor-2） denatured with 8 mol/L urea and 10 mmol/L dithiothreitol at pH 7.2. The refolding of FGF-2 was performed by directly diluting denatured FGF-2 into a refolding buffer containing Eudragit S-100. The ability of Eudragit S-100 to enhance protein refolding level was investigated using MTT method, fluorescence emission spectroscopy and reverse phase HPLC. On the other hand, the result shows the ability of Eudragit S-100 to enhance the refolding level of protein is due to the interaction between Eudragit S-100 and oositivelv charaed FGF-2.

Heterologous Expression of Isopentenyl Transferase(IPT) Gene Directed by Senescence Associated Receptor Protein Kinase(SARK) Promoter in Arabidopsis

[ Objective ] This study aimed to investigate the expression of IPT gene directed by GmSARK promoter in Arabidopsis. ~ Method J IPT gene and C.m- SARK promoter were respectively cloned to construct plant expression vector and transform Arabidopsis. Tl transgenie plant lines were detected by PPT （ phosphino- thricin） herbicide selection and treated under drought and dark conditions for semi-quantitive RT-PCR analysis. E Result] GmSARK： ：IPT fusion gene was success- fully cloned and the plant expression vector p3301-GmSARK-IlYF was constructed. RT-PCR analysis showed that the target gene was expressed in T1 transgeuie plant lines at the mRNA level. [ Conclusion] This study laid the foundation for further investigating the roles of IPT gene directed by GmSARK promoter in plant stress resistance.

Cloning of a Vacuolar H^+-pyrophosphatase Gene from the Halophyte Suaeda corniculata whose Heterologous Overexpression Improves Salt,Saline-alkali and Drought Tolerance in Arabidopsis

Salt,saline-alkali conditions,and drought are major environmental factors limiting plant growth and productivity.The vacuolar H＋-translocating inorganic pyrophosphatase（V-H＋-PPase） is an electrogenic proton pump that translocates protons into vacuoles in plant cells.Expression of V-H＋-PPase increases in plants under a number of abiotic stresses,and is thought to have an important role in adaptation to abiotic stress.In this work,we report the isolation and characterization of the gene,ScVP,encoding a vacuolar inorganic pyrophosphatase（V-H＋-PPase） from the halophyte,Suaeda corniculata.Semiquantitative reverse transcription-polymerase chain reaction analysis showed that ScVP was induced in roots,stems and leaves under treatment with salt,saline-alkali and drought.Compared with wild-type（WT） Arabidopsis,transgenic plants overexpressing ScVP accumulated more Na＋ in leaves and roots,and showed increased tolerance to high salinity,saline-alkali and drought stresses.The germination percentage of transgenic Arabidopsis seeds was higher than that of WT seeds under the abiotic stresses.The root length of transgenic plants under salt stress was longer than that of WT plants.Furthermore,the rate of water loss during drought stress was higher in WT than in transgenic plants.Collectively,these results indicate that ScVP plays an important role in plant tolerance to salt,saline-alkali and drought stress.