Table of Content

28 February 2002, Volume 20 Issue 1

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论著

Screening and Identification of Egg Mimotope of Schistosoma japonicum

QIANMin;BAIYanjun;ZHANGPing;YANZizhu;WUZirong

2002, 20(1):  1-5. 

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　Objective To explore egg mimotope of Schistosoma japonicum that can be used in the development of diagnostic reagents for schistosomiasis.Methods By performing three rounds of biopanning in the affinity selection before picking out single clones for identification, target specific phages were effectively enriched from a random 15 peptides phage library with an immobilized mAb 6B12 which is specific to egg antigen of S.japonicum as a bait. By using ELISA, competitive ELISA with natural egg antigen as competitor, and Western blotting, 13 phage clones with high affinity and specificity to 6B12 were obtained and amplified from 400 single clones. Results DNA sequencing revealed that all the 13 selected single clones were identical in displaying gene sequence. Serum samples were tested by ELISA for the presence of IgG antibodies to the phages with mimic epitope, and showed that there was a significant difference between healthy volunteers and schistosomiasis patients. Conclusion It is possible that the phage display peptide antigen, egg mimotope of S.japonicum may be a replacement of natural egg antigen for the diagnosis of schistosomiasis.


Spatial Autocorrelation Analysis on Schistosomiasis Cases and Oncomelania Snails in Three Provinces of the Lower Reach of Yangtze River

YANGGuojing;ZHOUXiaonong;WANGTianping;LINDandan;HONGQingbiao;SUNLeping

2002, 20(1):  2-9. 

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　Objective To explore the spatial distribution of schistosomiasis cases and Oncomelania snails in the provinces of Jiangsu, Anhui and Jiangxi with the assistance of geographic information systems (GIS). Methods Epidemiological data of schistosomiasis in recent 20 years were collected, and the relevant GIS databases were established. The spatial autocorrelation analysis was carried out with ArcView 3.x, S.Plus, and Spatial Statistics software. Results Except for schistosomiasis cases in Jiangsu, the spatial distribution of schistosomiasis cases and Oncomelania snails in the three provinces were fitted to the spatial autocorrelation at a certain degree. Generally the autocorrelation coefficients (Moran′s I) in Oncomelania snails were higher than that in schistosomiasis cases. Conclusion Spatial autocorrelation analysis can be used to estimate the value of one variable in different spatial position, and it is a good way to find out the spatial cluster distribution in different stages.


Study on Molecular Phylogeny of Schistosoma sinensium Based on Mitochondrial Genes

ZHANGGuangjun;QIUChiping;QIUDongchuan;XIAMingyi*

2002, 20(1):  3-13. 

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　Objective To determine the phylogenetic position of Schistosoma sinensium in the genus Schistosoma using mitochondrial cytochrome C oxidase 1 (CO1) and NADH dehydrogenase 1(ND1) as molecular markers. Methods The genomic DNA of adult worms were extracted by the GNTK method. The target regions were amplified by PCR using specific primers. The PCR products were purified before ligation into the plasmid Zero-Blunt. Recombinant plasmids were amplified in E.coli, extracted and purified using routine methods and then sequenced using M13 primers (F/R) on a Licor long read autosequencer. Sequences of related schistosomes were retrieved from GenBank and aligned with our data in the sequence editor ESEE. Gene trees were constructed in PHYLIP and MEGA using both maximum parsimony and neighborjoining methods. For parsimony analysis, all characters were treated as unordered and with equal weights. At least 3 000 cycles of bootstrapping were carried out. For analysis in MEGA, all gap columns were deleted. The third position of codon was included. Results The nucleotide and amino acid sequences of CO1 and ND1 of S.sinensium were obtained. Conclusion The phylogenetic trees from these molecular data suggested that S.sinensium belongs to the Asian schistosome group, and the results coincided with the previous rDNA (ITS2 & LSU) analysis results.


Screening of Stage-Specific Expression Genes of Spirometra erinacei-europaei Plerocercoid by mRNA Differential Display Technique

LIUDianwu;ZHUBing;WANGXiaobo;YANHuimin;DINGYuexin

2002, 20(1):  4-17. 

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　Objective To screen stage-specific expression genes of plerocercoid of Spirometra erinacei-europaei. Methods RNA was extracted by the acid guanidinium thiocyanate-phenol-chloroform from plerocercoid and adult worm of Spirometra erinacei-europaei. Contaminated DNA in the RNA was digested by RNase-free DNase. cDNA was synthesized by using T₁₂MA, T₁₂MC, T₁₂MG and T₁₂MT primers, and PCR was then done using the same T₁₂MN and one random primers. The PCR products were fractionated on 8% denatured polyacrylamide gel, differential bands of plerocercoid found in the gel were cut out, amplified by PCR and sequenced after the gel was dried out and autoradiographed. Northern hybridization was conducted to identify the stage-specific expression genes. Results Eleven differential bands were selected from the gel and classified into 3 kinds of gene fragments by hybridization after they were amplified by PCR. The fragments 1 and 2 were confirmed to express specifically in plerocercoid by Northern hybridization, but the fragment 3 was expressed in both plerocercoid and adult worm. When the 3 gene fragments were homologically analyzed in GenBank, the sequence which was homologous with the fragments 1 and 2 was not found, but the fragment 3 had high homology with many kinds of 28S rRNA. Conclusion The gene expression of plerocercoid was different from that of adult worm probably because they live in different hosts. Two kinds of different gene fragments in plerocercoid were identified by mRNA differential display technique.


Prevention and Control of Intestinal Nematode Infection in Shanghai

CAILi;HUANGDesheng;MAXingbao;ZHANGBaoxiu;FUYinghua;GEHongyan

2002, 20(1):  5-20. 

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　Objective To evaluate the current status of intestinal nematode infection in Shanghai and make recommendations for further control activities Methods Retrospective review of the control program was made based on the change of nematode prevalence in Shanghai area since the 1950s, and challenges under the current situation were analysed. Results The intervention measures included chemotherapy, health education, sanitary disposal of human excreta and safe water supply. With the control strategy, socioeconomical development and the change of farming patterns, the prevalence of intestinal nematode infection in population was reduced by 88.5%, from 62.6% in 1955 to 8.2% in 2000. Among them, ascaris infection decreased by 89.0%, from 52.1% to 6.3%, hookworm infection decreased by 99.0%, from 12.9% to 0.1%, but pinworm infection was still as high as 18.9% in 1999. Conclusion Prevalence of nematode infection in Shanghai was considerably reduced. To match it with the current socio economical development in the Municipality, however, more needs to be done. Sustainable control activities and surveillance are recommended.


A Case-Control Study on Risk Factors for Advanced Schistosomiasis Japonica

YUANZhao-kang;ZHOUXiao-jun;ZHENGHui-lie;LIUHan-qiang;YANTao;CHENNian-gao;GUXiao-nan;WANGWei-zhou;LIGuo-hua

2002, 20(1):  6-24. 

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　Objective To investigate risk factors for the development of advanced schistosomiasis. Methods The case-control study was designed with a match of 1∶1 and 1∶2. Healthy persons and chronic schistosomiasis patients were used as control. Each group was composed of 213 cases. Items investigated included: history of schistosomiasis and treatment, exposure to the contaminated water, social-economical condition and nutritional status, other concomitant diseases. Cellular and humoral immunity, HBVMs and ABO blood groups were also detected. Statistical analysis was performed by 1∶1 and 1∶2 matched single and stepwise conditional logistic regression analysis with SAS software. Results By stepwise conditional logistic regression analysis, it was revealed that number of schistosomiasis examinationOR=1.168-1.311), interval from first infection to last treatmentOR=1.142), interval from first infection to this investigation OR=1.089), HBsAg+OR=4.683-10.759), HBcAb+ OR=2.873), HBsAg++HBeAb++HBcAb+OR=7.64) were risk factors of developing advanced schistosomiasis. The average living space and cellular immunity were lower in advanced schistosomiasis patients than others. No association was found between advanced schistosomiasis and ABO blood groups. Conclusion The development of advanced schistosomiasis is associated with repeated infections, and delayed or incomplete treatment. Combined infection with hepatitis B, poor socio-economic conditions and impaired cellular immunity may increase the pathogenetic risk of schistosomiasis.


Epidemiological Study on Taeniasis and Cysticercosis in Shandong Province

LIUXin;ZHAOZhong-ping;WANGong-qun;FUBin;LIGui-ping;CHENXi-xin;MIAOFeng;ZHAOChang-lei;LIShun-ping;LIWen;FUZhao-yi;GAOChang-lan;DENGXu-li

2002, 20(1):  7-28. 

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　Objective To investigate current epidemiological status of Taenia solium infection and cysticercosis in Shandong Province. Methods By house to house interview in the field, fecal examination and serological tests, the prevalence data of taeniasis and cysticercosis in human and pig population, and epidemiological factors in relation to the diseases were carried out. Results The prevalence of Taenia infection and cysticercosis in human population were 0.048% and 0.057% respectively. The sero-positive rate of the specific IgG-4 of anti-Cysticercus was 1.91%. The prevalence differed among occupations and from region to region, but there was no significant difference between men and women, city and suburb. Unhealthy eating and unhygienic habits commonly practised among residents, 92.3% of the families have "latrines connected to pigsties". The surrounding sanitation and the disposal of fecal material were poor. The detection rate of porcine cysticercosis was 0.06%, and the positive rate of anti-Cysticercus antibody in pigs was 1.99%. Conclusion The prevalence of taeniasis and cysticercosis is decreasing. However, the endemic area is expanding and the epidemiological factors are still existing. Continued effort is therefore needed for sustain the control programme.


Sequence Difference of Ribosomal DNA Second Internal Transcribed Spacer in Anopheles minimus in Different Localities

ZHOUShui-sen;TANGLin-hua;GUZheng-cheng;WANGYi

2002, 20(1):  8-31. 

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　Objective To compare the sequence difference of the ribosomal DNA second internal transcribed spacer ITS2) in Anopheles minimus from Yunnan, Hainan, Guangxi of China and from Thailand. Methods Single mosquito′s legs were digested to extract DNA; the rDNA-ITS2 region was amplified by specific primers and the PCR products were purified, sequenced and analysed. Results Two different kinds of ITS2 sequences, temporarily named as An.minimus A and An.minimus C, were found in this study. The length and GC contents of ITS2 region in species A and species C are 481 bp, 54.04% and 483 bp, 54.23%, respectively. Two species differed by 5.8% in the ITS2 sequences owing to 22 fixed nucleotide substitutions and indels. Conclusion Two cryptic species, An.minimus A and An.minimus C, were found in the research localities.


Obtaining and Construction of a Novel Gene from Schistosoma japonicum by Expressed Sequence Tags

LIYan;YUXin-bing;WUZhong-dao;LIHui-ting;BAOJun-ying;SHAOXiao

2002, 20(1):  9-34. 

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　Objective To look for new candidate vaccine molecule and characterize new genes from Schistosoma japonicum. Methods New genes of S.japonicum were obtained through expressed sequence tags and analyzed on line. One interest cDNA was cloned into anti-sense eukaryotic expression vector. Results An interest cDNA JAYL0230 was obtained. Analysis showed that homology existed between its deduced amino acid sequence and defender against apoptotic death 1 of human and pig, etc. Its anti-sense cDNA was cloned into eukaryotic expression vector pEGFP-N3. Conclusion The combination of expressed sequence tags and bioinformatics is an effective way to find novel genes of creature. Construction of anti-sense eukaryotic vector is helpful in studying gene′s function.


Effect of MNNG on Ornithine Decarboxylase Activity in Cells from Adult Schistosoma japonicum

FANHong;HUANGMin;WANGQian;LIMan-jun

2002, 20(1):  10-36. 

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　Objective To observe the change of ornithine decarboxylaseODC) activity in cells from adult Schistosoma japonicum after the cells were treated with N-Methyl-N-Nitro-N-Nitrosoguanidine MNNG). Methods The cells were treated with MNNG at a concentration of 3 μg/ml for 48 hours after the cells being incubated for one week. The cells were then cultured with RPMI-1640 containing 10% calf serum. ODC activity was detected with spectrophotography. Results ODC activity rose significantly in two to three weeks after the cells were treated with MNNG. Conclusion There was ODC activity in cells from adult S.japonicum and MNNG has an effect to reinforce ODC activity in the cells.


Study on Inducing an Artemisinin-resistant Line of Plasmodium berghei

CHENYing-dan;LINBao-ying;ZHANGJia-xun;

2002, 20(1):  11-38. 

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　Objective To induce a line of Plasmodium berghei with resistance to artemisinin. Methods The major methods included blood transmission from passage to passage and progressive increase of drug pressure. Results The resistant lines were developed by different protocols: A) The initial dosage of artemisinin was 126.2 mg/kg which was increased by 60 mg/kg for the next passage and boosted by 126.2 mg/kg for every other passage. As developed to passage 60 and 76, the resistant index was 18.39∶1 and 14.89∶1 respectively, then decreased gradually. For passage 108, the dosage was 8 862.5 mg/kg, but the resistant index was only 10.49∶1. B) Using passage 66 from A) as the source, a dosage of 4 000 mg/kg was given each week, the resistance of the passage 40 increased significantly with an index of 27.5∶1. C) Using passage 19 of B) as the source, drug was administered at the dose of 2 000 mg/kg each week. The resistant index of passage 15 was 17.41∶1. Conclusion Line of P.berghei with medium level resistance to artemisinin was established.


实验报道

Construction and Characterization of the cDNA Library from Schistosoma japonicum Cercariae

CHENXiao-guang;LIHua;PENGHong-juan;SHENShu-man;FUNGMing-chiu

2002, 20(1):  12-41. 

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　Objective To construct a cDNA library from Schistosoma japonicum cercariae. Methods Total RNA was extracted from 500 000 S.japonicum cercariae and used to synthesize the double-stranded cDNA and cloned into the TriplEx2 vector using "SMART cDNA Construction Kit". Results The primary titer of the constructed cDNA library is 1.8×107 pfu/ml and the titer of amplified library is 2.5×1010 pfu/ml. The average size of inserts is 1.075 kb. The recombinant efficiency is 94.4%. The full length cDNA of S.japonicum TPI and JF-2 genes was successfully amplified from the library. Conclusion A cDNA library of S.japonicum cercariae has been constructed successfully.


Comparative Effect of Different Media in in vitro Cultivation of Trichomonas vaginalis

GENGZhi-hui;HANShu-mei;LIULi;SHIYu-lu;LIShu-hong

2002, 20(1):  13-44. 

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　Objective To investigate the optimal condition for in vitro cultivation of Trichomonas vaginalis for obtaining a better harvest of T.vaginalis. Methods An isolate of T.vaginalis from clinical specimens was cultivated in three different media with initial inoculation of 9.0×104/ml under pH 5.6. Results There was distinct difference after 96h incubation in the cumulative harvest of T.vaginalis. The highest harvest was received in cysteine/liver/peptone/maltose medium, followed by the liver/peptone/maltose medium and soybean/liver/peptone/maltose medium. Conclusion The cysteine/liver/peptone/maltose medium may be a suitable environment for in vitro multiplication of T.vaginalis.