Objective To construct and evaluate a novel PAMAM dendrimer vector-DNA vaccine for schistosomiasis japonica.Methods Lysine was used to modify 4.0G PAMAM.and the modified product PAMAM-Lys was synthesized.Agarose gel electrophoresis was used to confirm the composite ratio of plasmid DNA and dendrimer.Micrestructure of the compound was observed by using transmission electronic microscopy,and the stability was analyzed by using electrophoresis.The viability of the cells transfected with dendrimers was evaluated by using a MTT technique in vitro.Fiftyty mice were immunized with purified plasmid pJW4303,pJW4303-Sj23 dendrimer PAMAM-Lys and compound PAMAM-Lys/pJW4303-Sj23,respectively.The specific antibodies of the mice in each group were detected to access the immunoreactivity.Results The agarese gel electrophoresis showed that when the charge ratio of the dendrimer vector and DNA was between 2 and 4,the positive and negative charges could be counteraeted completely,and the compound was blocked completely by DNA electrophoresis.The obscrvation results with transmission electronic microscopy showed that the composition of dendrimer vector and DNA caused shrink of DNA structure.Dendrimer-DNA compound had a good stability.MTT showed the modified dendrimer vector and DNA compound system produced a lower cell toxicity on 293T cell than the unmodified Ones.Thk levels of specific antibodies of the mice immunized with PAMAM-Lys/pJW4303Sj23 were significantly higher than those of the mice immunized with naked DNA vaccine(P<0.05).Conclusions The lysinemodified PAMAM-lys is an excellent vector,and has an appropriate biocompatibility.Lysine-modification can reduce the cell toxicity of PAMAM dendrimer significantly.PAMAM-Lys can enhance the immunoreactivity of DNA vacmine which merits further application in schistosomiasis DNA vaccine.

OBJECTIVETo identify the egg antigens related to the formation of hepatic granulomas and fibrosis of Schistosomiasis japonica.

METHODSThe egg cDNA library of Schistosoma japonicum (S. japonicum) was constructed and screened by immunological methods with the pooled sera of advanced schistosomiasis patients. The inserted foreign DNA fragments of positive clones were sequenced. The sequence data were analyzed using Wdnasis 2.5 and compared with Genebank data using blast software.

RESULTSEighty-one clones containing recombinant DNA fragments were obtained from the egg cDNA library of S. japonicum by immunological screening. The DNA sequences of all clones belonged to the miracidial antigen family. The longest cDNA fragment was 1604 bp, which contained an open reading frame of 351 bp, which encoded a protein of 1 2913.35 daltons.

CONCLUSIONThe cDNA sequence of the miracidial antigen of S. japonicum (Chinese strain) was obtained for the first time.

Animals ; Antigens, Helminth ; genetics ; Base Sequence ; China ; DNA, Complementary ; analysis ; Ovum ; Schistosoma japonicum ; genetics ; immunology

Objective To evaluate the toxicity of suspension concentrate of niclosamide(SCN)for molluscicide in the field.Methods According to the state standard of the People's Republic of China "The methods of toxicity test for agriculture register",GB15670-1995,the experiments of acute toxicity on rats and fish were carried out.Results LD50(s)of SCN via mouth and skin with rats were more than 5 000 mg/kg respectively,and LC50(s)of SCN via inbreathe with rats were more than 5 000 mg/m3.Based on the classification of appraising criterion on acute toxicity test,it belonged to a feebleness toxicity degree.The eye and the skin stimulating tests with rabbits showed that it did not irritate the eyes and the skin.For fish,its acute toxicity was slightly lower than that of pure niclosamide,and markedly lower than that of pure niclosamide ethanolamine salt and WPN.Conclusions SCN belongs to a feebleness toxicity degree and has a lower toxicity to fish.It should be a useful molluscicide in endemic areas of schistosomiasis.

Objective To evaluate the molluscicidal effect of colistin E on Oncomelania hupensis. Methods The molluscicidal effect of colistin E on O. hupensis was checked by using the immersion method and spraying method. The toxicity of colistin E on fish was observed by using the toxic test. Results The snail mortality of each group was 100% when the snails were immersed in the colistin E solutions at a concentration of 5. 0, 1. 0 g/L for 24, 48 h and 72 h separately. When the snails were immersed in the colistin E solution at a concentration of 0. 5 g/L for 24, 48 h and 72 h, the death rates were 95% , 100% and 100% respectively; when the snails were immersed in the colistin E solution at a concentration of 0. 1 g/L for 24, 48 h and 72 h, the mortality was 90%, 95% and 100% respectively; when the snails were immersed in the colistin E solution at a concentration of 0. 01 g/L for 24, 48 h and 72 h, the mortality was 70%, 86% and 100% respectively. The snail mortality by the spraying method in a dose of 35, 70, 140 mg/m2 of colistin E was 60%, 100% and 100%. The result of toxic test showed that the toxicity of colistin E on fish was low. Conclusion Colistin E is an effective molluscicide, and is worthy of investigation further.

Objective To develop a novel synergism compound suspension concentrate of niclosamide and chlorphoxim (Co-SCN) and sdudy its characteristics. Methods Niclosamide and chlorphoxim were milled by a ball mill and mixed with different amounts of wetting agent. disper-sant agent, thickener, and water etc. , to develop Co-SCN, and the pH value, thickener, grain size were evaluated. The ultraviolet absorption spectrum of niclosamide and chlorphoxim were measured. The content of niclosamide and chlorphoxim in the solution were assayed by HPLC. Results Co-SCN was a gray thickener fluidity liquid. It was very easy to disperse and could be mixed with water in any proportion. Its pH was 8. 65 and thickener was 137 mpa? s. The grain sizes (diameter) were from 0. 138-19. 953 ?m. Of them more than 95. 6% was smaller than 10 ?m and more than 82. 24% was smaller than 5 ?m. There were three peaks of ultraviolet absorption spectrum for niclosamide: 210, 234 nm and 334 nm respectively. One peak of chlorphoxim was at 269 nm. The novel formulation contained 20.64% niclosamide and 5.26% chlorphoxim. The suspension stability of Co-SCN was 100% for 2 hours and 89. 14% for 4 hours, and otherwise WPN in water was speedy sediment. Conclusion The novel synergism compound suspension concentrate of niclosamide and chlorphoxim is a stable quality and standard formulation.

This study reported the primary application of FA-ELISA from 107-121kDa fration antibody of Schistosoma Japonicum for detection of the short-term antibody in patients with schistosomiasis. The result showed that this method provided high sensitivity (with positive rate of 93. 33% with 30 cases of schistosomiasis) and good specificity (no false postive in 60 health objects). When one group of schistosome patients were examined with FA -ELISA and with the routine SEA-ELISA before chemotherapy and at 8 months,1 year and 1. 5 year after treatment,it showed good property for evaluation of chemotherapy efficacy with FA -ELISA,which was much better than the routine method.

Objective To identify the trend of endemic situation among surveillance sites in Jiagsu Province from 2000 to 2002. Methods Twelve schistosomiasis surveillance sites were es-tablished ,and the longitudinal, surveillance was carried out. Results The related index of snail increased in most of surveillance sites, the rates of positive snails rose rapidly in marshlands. The infection rates of Schitosoma janponicum of cattle decreased and infection rates of human were relatively steady. However, there was still the danger of heavy endemic. Conclusion Current control strategies can not effectively adapt to the endemic situation of schistosomiasis, although which have some effects on control of morbidity. We need to study the new characteristics and rule of the endemic of schistosomiasis, and make out more effective control strategies which can suit with the current society, economies and nature environment.

Objective To understand whether the breeding time of snails influences the evaluation on molluscicidal efficacy against Oncomelania snails so as to make a standardization of methods for screening molluscicides in laboratory. Methods Snails collected from the endemic areas in Nanjing and Tongling cities bred for 1,6,11,16,21.31,61 and 91 days respectively, and then were immersed in 1.000 0,0.500 0,0.250 0,0.125 0,0.062 5 and 0.031 3 mg/L solution of niclosamide for 24 and 48 hours at 25℃ in laboratory. Results One hundred percent killing rate was achieved in the groups of the snails bred for 1 - 11 days and immersed in 1.0 mg/L niclosamide for 24 hours. The LC_(50) concentrations of snails collected from Nanjing, Jiangsu Province and immersed for 24 hours varied from 0.094 7 to 0.133 9 mg/L, and for 48 hours from 0.071 8 to 0.092 6 mg/L.Those of snails collected from Tongling, Anhui Province for 24 hours varied from 0.082 5 to 0.103 9 mg/L, and for 48 hours from 0. 071 8 to 0.082 5 mg/L. The molluscicidal effect was unstable in the groups of snails bred for more than 16 days. There was a significant difference (X_(Nanjing24 h)~2 = 22.26,P

Objective To design the Internet geographic information system (GIS) on schistosomiasis of Jiangsu Province using the technology of WebGIS. Methods Based on the GIS database of schistosomiasis, the active model of WebGIS on schistosomiasis was developed with the software of ArcIMS. Results The WebGIS of schistosomiasis has been developed and it has been running on the intranet of Jiangsu Institute of Parasitic Diseases. The system would manage the geographic database and attribute material database, and it would provide the function of query, display, analysis, statistics, export, etc. Conclusion It is feasible to design the WebGIS of schistosomiasis, which provides the basics of developing the Management Decision Systems of Schistosomiasis of Jiangsu Province.

Objective To construct, express and purify human scFv antibody (S1) against the recombinant SAG1 of Toxoplasma fused to magainin, and observe its protective effect against Toxoplasma in infected mice. Methods The S1 scFv antibody gene amplified from phagmid S1/pIT-2 fused to magainin was cloned into procaryotic expression vector pET-32c. The recombinant plasmid S1M/pET-32c proved by DNA sequencing was transformed into E.coli BL21, and induced for fusion expression of S1M with IPTG. The expressed S1M was purified with Ni 2+ chelating HiTrap HP column and detected with SDS-PAGE. The effect of reduction of infection of Toxoplasma was observed through in vivo and in vitro experiments in mice. Results The fused gene of S1 and magainin was successfully cloned into procaryotic expression vector pET-32c proved by DNA sequencing. The recombinant S1M protein about 43 kDa was expressed in E.coli as inclusion body, and prepared with Ni 2+ column purification. Tachyzoite of Toxoplasma preincubated with S1M showed decreased infectivity in mice, the result of in vivo experiments showed that mice treated with S1M hadlonger survival time than the mice untreated. Conclusion The purified targeting antimicrobial peptide S1M could reduce the infectivity of tachyzoites of Toxoplasma in a certain extent and has a potential value for biological therapy of toxoplasmosis; otherwise, the constructed targeting antimic robial peptide S1M also provides a new model for biological therapy of toxoplasmosis.