Schistosoma japonicum strains: differentiation by RAPD and SSR-PCR.

Eight geographical isolates of Schistosoma japonicum from Taiwan and mainland China and one isolate of Schistosoma mansoni were studied by RAPD analysis using six arbitrary primers and SSR-PCR analysis using a (CA)8RY primer. The genetic distance was determined by the percentage of unshared bands. The RAPD and SSR-PCR results showed that the genetic distance between S. mansoni and S. japonicum was more than 0.900 and 0.850 respectively; the genetic distance between the eight geographical isolates of S. japonicum was 0.000 to 0.232 and 0.066 to 0.368 respectively. These results demonstrated the usefulness of RAPD and SSR-PCR for showing the differences of inter- and intra-species of Schistosoma. The results also suggest that there is genetic diversity among the different geographical strains of S. japonicum in China.

COMPARISON OF PRELIMINARY DETECTION RESULTS OF SEVERAL TOXOPLASMA GONDII ELISA TEST KITS / 中国人兽共患病学报

Aim Five types of civil Toxoplasma gondii ELISA test kit were used to the detected specimen which proved to be the same, foreign-made test kit was used to examine the positive specimen given by these five types of test kit, as to make comparison about quality of test kit. Results IgG-ELISA A,B kits positive showing rates (sensitive)are all 60％ ,the corresponding rate between A&B is merely 50％ ,the specifics are 35％&90％. C, D,E kits' positive showing rates (sensitive)are 30 ％, 60 ％, 70 ％ the specifice are 75 ％, 54 ％, 87 ％. The result about examining the probes given by A, B, D, E kit :IgG corresponding rates are better, which are all more than 90％ ;IgM corresponding rates are all more than 60％. It turn out that, according to the civil conditions of ELISA test kit, we suggest that besides the quality being improved in, all kinds of test kit should be used combinatively, so as to avoid neglect and mistake on examination, and we should be cautious in examining.

Genetic Variation of Two Mitochondrial DNA Molecules from Three Isolates of Oncomelania hupensis / 中国寄生虫学与寄生虫病杂志

Objective To study the genetic variation of two mitochondrial DNA molecules (CO1 and Cytb gene) of Oncomelania hupensis isolated from different areas. Methods Snails were collected from Jingxi of Guangxi,Yueyang of Hunan and Eryuan of Yunnan. Genomic DNA was extracted from the snails,Co1 and Cytb gene fragments were amplified by PCR,then purified and sequenced. Sequences of each isolates were edited by using Clustal W(1.82) software,and the nucleotide composition,transition and transversion were accounted by using MEGA(3.1) software. The genetic distances were computed with Kimura method and phylogenetic trees were constructed with UPGMA and MP method respectively. Results CO1 and Cytb gene fragments were about 700 bp and 600 bp(including 2 primers) respectively. A total of 106 mutation spots (15.9%) were tested in CO1 homological nucleotides,and 165 mutation spots (28.5%) were tested in Cytb homological nucleotides. The distance matrix between Guangxi isolate and Hunan isolate was 0.051 and 0.031 for CO1 gene and Cytb gene respectively;while that between Guangxi and Yunnan isolates was 0.158 and 0.405 respectively. Phylogenetic trees constructed by UPGMA and MP took on the similar topo-structure:isolates of Guangxi and Hunan clustered into one group,while the Yunnan isolate exhibited as another group. Conclusion Oncomelania hupensis in Guangxi,Hunan and Yunnan are of relatively rich polymorphism in CO1 and Cytb genes in general.

Studies on the Protective Effect of the Mutant of Sj23 DNA Vaccine against Schistosomiasis / 中国寄生虫学与寄生虫病杂志

Objective To investigate the protective immunity of the vaccine against schistosomiasis,a mutant of Mr 23 000 membrane protein DNA(Sj23DNA) without the homologous sequence of ME491.Methods The mutant of Sj23 DNA with no homologous sequence of ME491 on the cell membrane of human melanoma was obtained by overlap PCR.The mutant was transfected into human embryonic kidney cells of the line HEK293.Indirect fluorescent antibody test(IFAT) was used to detect the expressed protein.Expression of the mutant of Sj23DNA in muscular cells of mice was conducted through vaccinating the mouse with 100 ?g purified plasmids by injecting them into the quadriceps muscle of thigh.Four weeks after the immunization,the quadriceps muscles were taken and cryostat sections were prepared for detecting the expression by IFAT.Forty BALB/c mice were randomly divided into four groups and injected with the mutant of pcDNA3-Sj23 plasmid DNA,pcDNA3-Sj23 plasmid DNA,pcDNA3 blank plasmid(100 ?g per mouse) and sterile saline(30 ?l per mouse) respectively.Four weeks after the immunization,mice were challenged with cercariae(40?2 cercariae per mouse) by abdominal skin penetration.Mice were then killed 6 weeks later,perfusion and squash methods were carried out to collect the adult worms and the number of eggs per gram of liver tissue was calculated.Worm and egg reduction rates were used to evaluate the protective immunity.Results Specific fluorescence was demonstrated in muscular cells of mice vaccinated with the mutant of pcDNA3-Sj23.The worm reduction rate and egg reduction rate were 40.3% and 42.8% respectively in the mutant of pcDNA3-Sj23 group,which were higher than those in the pcDNA3-Sj23 plasmid group(33.1% and 28.9% respectively).The difference between these two groups was significant(P

Studies on the Genetic Variation of Two Mitochondrial DNA Molecules of Schistosoma japonicum / 中国寄生虫学与寄生虫病杂志

Objective To study the variation of Schistosoma japonicum through two mitochondrial DNA molecules. Methods Genomic DNA was isolated with kit, and the mitochondrial NADH dehydrogenase 1(ND1) and cytochrome c oxidase I (COI) gene fragments were amplified by polymerase chain reaction(PCR) and sequenced. The gene trees were constructed and the acquired data were analyzed with the help of bioinfotmatics. Results The gene trees showed that the Taiwan isolate and the mainland isolates can be divided in two groups: a group from the hilly region (Yunnan and Sichuan), another group from the lake region (Hunan, Jiangxi and Anhui); isolates from Hubei are at a different position on the gene trees. Conclusion There are variations among the geographic isolates of Schistosoma japonicum in China, nevertheless, they have close kinship.