Cloning, eukaryotic expressing and function analysis of Schistosoma japonicum apoptosis gene Sjcaspase3 / 生物工程学报

For further research of the apoptosis mechanism of Schistosoma japonicum (S. japonicum). The cDNA encoding Sjcaspase3 of Schistosoma japonicum was amplified by polymerase chain reaction (PCR) technique, which contained 900 nucleotides and encoded 299 amino acids. The theory molecular weight and isoelectric point (PI) of the deduced protein is 33.5 kDa and 6.39, respectively. Real-time PCR was used to analyze the transcription profiles of Sjcaspase3 at different development stages of S. japonicum. The results showed that this gene was expressed in all stages of S. japonicum with the highest expression in 21d worms, and the level of gene transcription in 42 d female worms was higher than that of male worms. The recombinant plasmid pXJ40-FLAG-Sjcaspase3 was constructed and transfection into Hela cells successfully. Real-time PCR and Western blotting analysis showed Sjcaspase3 was successfully expressed in Hela cells. Enzyme activity analysis revealed that recombinant Sjcaspase3 possessed the activity to cut substrate DEVD. Flow cytometry proved that Sjcaspase3 could induce early apoptosis of Hela cells. The results provide the basis for proceeding further study on the biological function of Sjcaspase3 and better understand the apoptosis mechanism of S. japonicum.

Cloning, expression of gene SjOST48 from Schistosoma japonicum and evaluation of the immunoprotective efficacy of rSjOST48 in mice / 生物工程学报

To identify SJCHGC01743 gene of Schistosoma japonicum and evaluate the potential of the recombinant protein as a new vaccine candidate for schistosomiasis, polymerase chain reaction (PCR) technique was used to amplify the cDNA of the gene and real-time RT-PCR was used to analyze the transcription profiles of SJCHGC01743 at different development stages. Recombinant plasmid was successfully constructed and transformed into competent Escherichia coli BL21 (DE3). Then the recombinant protein was expressed, purified and emulsified with ISA206 adjuvant to immunize BALB/c mice for three times. The immunogenicity was confirmed by Western blotting and tissue localization was detected by indirect immunofluorescent assay. The specific antibody level was detected by ELISA. The immunoprotection of rSjOST48 was evaluated by the reduction in worm and egg counts in mice. A cDNA with 1 248 nucleotides was isolated from 28-day-old schistosomes cDNAs by PCR. Sequence analysis revealed that SJCHGC01743 was a 48-kDa subunit of the oligosaccharyltransferase complex (OST48) and named as SjOST48. Real-time PCR analysis indicated that this gene was expressed in all investigated stages and had the highest expression level in 28 d worms, the level of gene transcription in female worms was significantly higher than that of male worms. Then recombinant plasmid pET28a(+)-SjOST48 was successfully constructed and expressed in E. coli BL21 (DE3). Western blotting analysis showed that rSjOST48 had good immunogenicity. Indirect immunofluorescent analysis revealed that SjOST48 was mainly distributed on the tegument of the worms. The result of ELISA indicated that the rSjOST48 vaccinated group could induce a significant increase in the level of specific IgG, IgG1 and IgG2a. An immunoprotection experiment showed that the vaccination of rSjOST48 in mice induced 32.62% (P < 0.05) reduction in the numbers of worms and 57.61% (P < 0.01) in eggs in liver, compared with that of the control group. This study provides the foundation for proceeding further research on the biological function of SjOST48 and screening new vaccine candidates for schistosomiasis.

Mercury Speciation Determination in Fish and Soil Samples Based on Low Pressure LC-AFS Combined with Rapid Sample Pretreatment / 分析化学

The build-in low-pressure monolithic column combined with hydride generation atomic fluorescence spectrometry ( HG-AFS ) was employed for speciation analysis of fish meat. The sample pretreatment and separation approach could be accomplished within 30 min. The proper amount of fish sample was weighed and smashed into puree. The extraction solution composed of 10% HCl, 1% thiourea, and 0. 15% KCl was added before loaded into the automatic temperature controlled vertex system with 2000 r/min. The sample solution was separated through Merck monolithic column, with 3% ( V/V) acetonitrile, 30 mmol/L amonium acetate and 0. 03%(V/V) 2-mercaptoethanol (2-ME) as the eluent. The after-column eluent was digested by novel UV digestion device with pipeline sintered into the lamp, and then detected by hydrid-generation AFS. The rapid LC separation enabled fast mercury speciation of fish sample within 10 min. The different UV lamp digestion effects, eluent components, carrier gas, shield gas, lamp current, as well as PMT working power was optimized. Under the optimal conditions, the robust system achieved detection limits (DL) of 0. 15 μg/L and 0. 14 μg/L for methylmercury and HgⅡ, respectively. The RSD (n=7) was less than 5%, the linear correlation coefficient was 0 . 999 , and the matrix spiked recovery was in the range of 85%-110% for Hg speciation. This method was used for the determination of Hg speciation in fish and soil samples, and was proofed to be a reliable, easy approach for daily inspection.

Cloning,expression and immuno-protection analysis of a gene encoding tro-ponin T of Schistosoma japonicum(SjTnT) / 中国血吸虫病防治杂志

Objective To clone cDNA encoding troponin T of Schistosoma japonicum(SjTnT),and evaluate the protective efficacy induced by recombinant SjTnT in BALB/c mice against S. japonicum challenge infection. Methods The SjTnT gene was amplified from 28-day-schistosome cDNAs by PCR and then subcloned into pET28a(+). The recombinant SjTnT protein (rSjTnT)was expressed in Escherichia coli BL21(DE3)cells. The serum specific to rSjTnT was prepared by immunized BALB/c mice with the recombinant antigen,and the immunogenicity of rSjTnT was detected by Western blotting and ELISA. The immuno-protective efficacy induced by rSjTnT in BALB/c mice was evaluated according to the reduction in worm and egg counts. Results The cDNA encoding SjTnT was successfully cloned and expressed in E. coli. Western blotting showed that rSjTnT had a good immunogenicity. The high level of specific IgG antibodies was detected,and 33.89% worm reduction and 43.94% liver egg reduction were obtained in mice vaccinated with rSjTnT combined with Seppic 206 adjuvant compared with those in the adjuvant control group. Conclusions rSjTnT could induce partial immuno-protection against S. japonicum infec-tion in BALB/c mice. This study provided a basic for understanding the biological function of SjTnT.

Cloning, expression and protective efficacy evaluation of radiation sensitive protein 23 (RAD23) from Schistosoma japonicum / 生物工程学报

Radiation sensitive protein 23 (RAD23) is a nucleotide excision repair (NER) protein that plays an important role in Ubiquitin-proteasome pathway (UPP). Schistosoma japonicum radiation sensitive protein23 (SjRAD23) cDNA sequences were amplified by PCR and cloned into pET28a (+) vector to construct recombinant expression plasmid pET28a(+)-SjRAD23. The recombinant protein was expressed as both inclusion bodies and the supernatant in Escherichia coli BL21 (DE3) cell. Immunofluorescence observation shows that SjRAD23 was mainly distributed on the tegument surface of the worms. ELISA assay reveals that specific IgG, IgG1 and IgG2a antibodies could be detected in the sera of rSjRAD23 immunized mice. Western blotting analysis shows that the recombinant SjRAD23 could be recognized by serum specific to soluble adult worm antigen of S. japonicum. BALB/c mice vaccinated with rSjRAD23 combined with 206 adjuvant revealed 35.94% worm reduction and 40.59% liver egg reduction when compared with that of the adjuvant control