ABSTRACT
Preparation of a poly (gamma-glutamic acid)-cisplatin conjugate was introduced and its in vitro antitumor effect was investigated. Poly (gamma-glutamic acids) was obtained by using fermentation methods. The hydrolyzed small molecular weight of poly (gamma-glutamic acids) was prepared by acid hydrolysis. The interaction between poly (gamma-glutamic acids) -cisplatin conjugate (PGA-CDDP) and DNA was investigated by PCR model. MTT assay was used to investigate the in vitro anticancer activity of the conjugate. Apoptosis assay of the conjugate was investigated by FCM assay and the in vivo toxicity was also proceeded. The results showed that the poly (gamma-glutamic acids) -cisplatin conjugate was obtained successfully and its yield is 10% - 12%. It has obvious antitumor effects on human liver tumor BEL7404 cells, human lung tumor H446 cells and human colon tumor RKO cells. At the same time, it also has apoptosis effects on the three kinds of tumor cell lines. The in vivo toxicity of PGA-CDDP was examined in normal mice and the results showed that the in vivo toxicity of this conjugate was significantly lower than that of free CDDP. In conclusion, the poly (gamma-glutamic acids) -cisplatin conjuate could be used as a potential clinic antitumor drug. The poly (gamma-glutamic acids) obtained by fermentation can be used as a valuable drug carrier system.
Subject(s)
Animals , Female , Male , Mice , Antineoplastic Agents , Pharmacology , Apoptosis , Cell Survival , Cisplatin , Pharmacology , Drug Carriers , Fermentation , Hydrogen-Ion Concentration , Polyglutamic Acid , PharmacologyABSTRACT
Human glutamate decarboxylase 65(hGAD65) is an enzyme that catalyzes the transformation of L-glutamic acid into ?-aminobutyric acid.It has been found that Type 1 diabetes mellitus(T1DM)is an autoimmune disease,in which pancreatic islet ?-cells are destroyed due to immune response mediated by autoantigen.hGAD65 is considered as a key autoantigen of the autoimmune response,so anti-hGAD65 antibody(hGAD65-Ab) is the most effective and specific immune marker for T1DM diagnosis,and hGAD65 can be used to detect hGAD65-Ab in serum of T1DM patients.The hGAD65 gene was cloned into pET32a(+),then the recombinant plasmid with hGAD65 was transformed into E.coli BL21(DE3) and expressed by IPTG induction.The fusion protein containing thioredox,hexahistidine and hGAD65(Trx-hGAD65) was mostly insoluble,but the band of soluble Trx-hGAD65 could also be detected by SDS-PAGE,and it was a great improvement compared with the results reported.Trx-hGAD65 was isolated from lysate and purified by immobilized metal ion affinity chromatography(IMAC).After enterokinase digestion and IMAC purification,hGAD65 with high purity was obtained.Detection of thin-layer chromatography(TLC) showed that both Trx-hGAD65 and hGAD65 had enzymatic activity,whereas Trx-hGAD65 had better stability.Furthermore,it was confirmed that Trx-hGAD65 was able to conjugate with hGAD65-Ab in the serum of T1DM patients by ELISA assay.In conclusion,Trx-hGAD65 instead of hGAD65 can be used for T1DM diagnosis,and its application in prophylaxis and therapy of T1DM is expectable.
ABSTRACT
The synthesized full-length hGLP-1 gene was cloned into pET-32a(+) to get the recombinant plasmid pET32-GLP-1, which could express a fusion protein containing thioredox, hexahistidine, and rhGLP-1 consecutively. The recombinant plasmid containing hGLP-1 was transformed into E.coli BL21 (DE3) and expressed by IPTG induction. The fusion protein was purified from lysates with Ni?IDA His?Bind affinity chromatography. rhGLP-1 with the purity of 90% was achieved after enterokinase digestion, Ni?IDA His?Bind affinity chromatography again, then was concentrated by ultrafiltration. The purified rhGLP-1 showed a single band on IEF gel with an isoelectric point between pH5.2 and pH5.85. ESI mass spectrometry showed that the molecular weight was 3355.0kDa as expected. rhGLP-1 was digested with trypsin followed by mass analysis and the peptide mapping produced two expected fragments with the molecular weights of 2097.7kDa and 1005.5kDa, respectively. The purified rhGLP-1 also showed obvious biological activity for both lowering plasma glucose and stimulating insulin secretion in mice.
ABSTRACT
The regulatory region and the signal peptide sequence of the sacB gene has been amplified by PCR using Bacillus subtilis chromosomal DNA as template, and an inducible secretion vector has been developed based on this sequence, which was ligated with Bacillus subtilis alkaline proteinase gene. Transform Bacillus subtilis DB403 with this vector, and the expression of the inserted Bacillus subtilis alkaline proteinase gene can be induced by addition of sucrose into the medium.
ABSTRACT
The fermentation conditions which affect C-15? hydroxylation o f 18-methyl-estr- 4-ene-3,17-dione were investigated. As the key step in the Hydroxylation, the dissolution of substrate was focused on. Tween80, MeOH, DMSO,?-CD and 2-HP?CD were studied to improve the dissolvability of 18-met hyl-estr-4-ene-3,17-dione.The other factors such as pH, substrate concent ration and aeration strategies which affected conversion rate were also resea rched. As a result, the conversion rate can be up to 60% in shake flask and ach i(eve 50% in fermentor,which would overcome the disadvantage of 15?-hydroxyl -18-methyl-estr-4-ene-3,17-dione chemosynthesis and provide a good techn ics to industry.
ABSTRACT
The degQ gene, amplified from Bacillus subtilis by PCR, was cloned to pUBS (sucrose induced secretion vector). After transformed into DB403, recombination named DB403(pUBSD) was formed. The results of the fermentation showed that degQ gene enhanced the expression of B. subtilis fibrin enzyme. The activity of the enzyme was increased to 2.2 times as the original one. In this article, the effects of different conditions, such as different kinds of sugar, different concentration of sucrose and different induced time were also be investigated and compared.