The identification of the Cryptosporidium ubiquitum in pre-weaned Ovines from Aba Tibetan and Qiang autonomous prefecture in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Cryptosporidium spp. are prevalent globally and sheep are an important zoonotic reservoir. Little data regarding the rates of Cryptosporidium infections in ovines in China are available. This study assessed the prevalence of Cryptosporidium spp. in pre-weaned ovines from Aba Tibetan and Qiang Autonomous Prefecture in the Sichuan province of China.</p><p><b>METHODS</b>A total of 213 fecal samples were collected from pre-weaned ovines and were examined microscopically (following modified acid fast staining). In addition, 18S rRNA genetic sequences were amplified from fecal samples by nested PCR and phylogenetically analyzed.</p><p><b>RESULTS</b>The prevalence of Cryptosporidium in the collected samples was at 14.6% (31/213) and four isolates identified by PCR belonged to the Cryptosporidium cervine genotype (Cryptosporidium ubiquitum) demonstrating that this species was the primary sheep species found in sheep in China.</p><p><b>CONCLUSION</b>The present study suggested that the high incidence of Cryptosporidium in sheep poses a significant public health threat and that surveillance practices must be established to prevent zoonotic disease of humans.</p>

Cloning and expression of the gene encoding hypoxanthine-guanine phosphoribosyltransferase of Schistosoma japonicum / 中国血吸虫病防治杂志

Objective To perform the cloning of the gene encoding Schistosoma japonicum Chinese-strain hypoxanthine-guanine phosphoribosyltransferase(HGPRT)and its expression in Escherichia coli.MethodsA couple of primers were designed with the BamHI restriction endonuclease site introduced in forward primer and SalI in reverse primer.Total RNA was isolated from adult worms of S.japonicum Chinese-strain(Anhui-strain,Sjc-A)and the SjcHGPRT gene was amplified by reverse transcriptase-polymerase chain reaction(RT-PCR).The PCR product and the prokaryotic expression vector pET28a were digested by both restriction endonucleases BamHI and SalI.The target DNA fragments were purified and cloned properly into pET28a.After identification by en-donucleases digestion,PCR and sequencing,the recombinant plasmid pET28a-SjcHG PRT was transformed into competent E.coli BL21 and expressed in the presence of IPTG.Results pET28a-SjHGPRT was sequenced and shown to be 99% and 83% identical in deduced amino acid sequence to that of S.japonicum Chinese-strain(Hunan-strain,Sjc-H)and S.mansoni HGPRT,respectively.The results of SDS-PAGE and Western blot revealed that the molecular weight of expressed protein was around 30 kDa and could be recognized by anti-His-G-HPR antibody and sera from mice and human with schistosomasis japonica.Conclusion The recombinant plasmid containing SjcHGPRT cDNA is successfully constructed and its expression protein(reSjcHGPRT)is also successfully purified.

Protective Immunity Induced by Recombinant Schistosoma japonicum Thioredoxin in Mice / 中国寄生虫学与寄生虫病杂志

Objective To investigate the protective immunity of the recombinant thioredoxin of Schistosoma japonicum(reSjcTrx)in mice. Methods Thirty 6-week old female C57BL/6 mice were randomly divided into 3 groups with 10 each: reSjcTrx with Montanide ISA720 adjuvant, adjuvant control, and infection control. Mice were vaccinated subcutaneously at week 0, 2, 4 with reSjcTrx emulsified in Montanide ISA720 adjuvant. The mice in adjuvant group was injected three times with Montanide ISA720 and saline only. Mice in infection control group were given no injection. Three weeks after final injection, each mouse was challenged with 30?1 cercariae of S. japonicum (Chinese strain). At the week six after challenge, all mice were sacrificed and perfused. The number of recovered worms and eggs from liver tissue of mice were counted. Sera were collected from mice before immunization, before challenge and before killing. The anti-SjcTrx antibodies in sera were detected with ELISA. Results ELISA showed a high level of specific IgG antibodies in mice immunized with the reSjcTrx. The worm reduction rate and egg reduction rate of reSjcTrx immunization group were 22.8% and 29.5% respectively, significantly higher than those of the control groups (P﹤0.05). SDS-PAGE and Western blotting revealed that the molecular weight of expressed protein was around Mr 14 000 and could be recognized by sera from rabbit infected with S.japonicum and from mice immunized with reSjcTrx. Conclusion The reSjcTrx induces certain protective immunity against schistosomiasis japonica in mice.

Preparation of DNA from Cryptosporidium parvum Oocysts for PCR Detection / 中国寄生虫学与寄生虫病杂志

Objective To establish three methods of DNA extraction from Cryptosporidium parvum oocysts and test by PCR. Methods After three freeze-thaw cycles, three kinds of templates were extracted from the oocysts by Chelex-100, phenol/chloroform or genomic DNA purification system kit, and used for PCR detection. According to the sequence of a C.parvum gene (L16996), a pair of primers was designed and synthesized, and used for PCR. The sensitivity of the template by Chelex-100 method was also tested by PCR. Results One 446 bp PCR product was observed by agarose gel electrophoresis for all three kinds of templates. The PCR sensitivity by Chelex-100 extracted DNA reached for detection of a specimen containing only 1/2 oocyst. Conclusion The three kinds of extraction can all be served as templates for PCR detection of C.parvum oocysts, while Chelex-100 method is simpler, quicker and more reliable for DNA extraction of the parasite.

Cloning, Expression and Analysis of the Heat Shock Protein of Cryptosporidium andersoni / 中国寄生虫学与寄生虫病杂志

Objective To clone and express the partial encoding sequence of Mr 70 000 heat shock protein of Cryptosporidium andersoni (CaHSP70) in Escherichia coli and identify the recombinant protein. Methods Total RNA was extracted from oocysts of C.andersoni isolated from Xuzhou, Jiangsu (XZ-BOV). The CaHSP70 gene was amplified by RT-PCR. The PCR product was cloned and then subcloned into pET28a vector, and the recombinant plasmids were transformed into E.coli BL21(DE3) subsequently. The expressed protein induced by IPTG was purified and identified by SDS-PAGE and Western blotting, and was further analyzed by relevant bioinformatics softwares. The specific IgG antibodies in mice immunized by rCaHSP70 were detected by Western blotting and ELISA respectively. Results The deduced amino acid sequence showed to be identical with that of C. andersoni Mr 70 000 heat shock protein (HSP70). The recombinant protein expressed in the form of inclusion body was about Mr 43 000. It could be recognized by anti-His G labeled HRP antibodies and all the sera from mice infected with C. andersoni and children infected with C. parvum as well as sera from mice immunized with rCaHSP70 respectively. The rCaHSP70 possibly had multiple domains and potential antigenic determinants. Phylogenetic analysis showed that XZ-BOV and C. andersoni were in the same clade. ELISA showed that the level of specific antibodies against rCaHSP70 in immunized BALB/c and C57BL/6 mice was significantly higher than that of mice before immunization. Conclusion The recombinant plasmid pET28a-CaHSP70 has been constructed. The purified rCaHSP70 exhibits high antigenicity and seems a potential candidate antigen for immunodiagnosis of cryptosporidiosis.

Isolation and Identification of an Isolate of Cow-origin Cryptosporidium sp / 中国寄生虫学与寄生虫病杂志

Objective To isolate and identify Cryptosporidium oocysts from feces of naturally infected cow. Methods Fecal samples were collected from Cryptosporidium infected cows confirmed by modified acid-fast staining method. Oocysts were isolated and purified with Sheather sucrose density gradient centrifugation technique. Genomic DNA was isolated with Chelex-100. Both primers were designed to amplify Cryptosporidium small subunit ribosome RNA gene (SSU rRNA) and Cryptosporidium oocyst wall protein gene (COWP), respectively. The PCR products were cloned into pGEM-T and pGEM-T Easy vector and sequenced subsequently. Homology and phylogeny were analyzed with BLASTn and MEGA software. Results The results suggested that the size of oocysts was (7.4?0.32)?m by(5.4?0.21)?m and the ratio of length and width was 1.37?0.07 (n=20). BLASTn revealed that the identity of SSU rRNA and COWP gene of Cryptosporidium isolated from cow to the counterparts of C.andersoni was 100% and 99% respectively. Phylogenetic reconstruction placed the isolated Cryptosporidium within the C.andersoni clade based on the sequence of SSU rRNA and COWP gene. Conclusion What isolated from naturally infected cow feces has been identified as C. andersoni.