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Determination of Circulating Antigen in Neurocysticercosis Patients by Monoclonal Antibody

Zengzhu GUO ; Minjun HUANG ; Yijun AN ; Song HUANG ; Hongjie JIANG

Journal of Tropical Medicine.2005;5(2):113-115.

Objective To detect circulating antigen (Cag) for diagnosing neurocysticercosis. Method ELISA was performed with monoclonal antibody 4B6 against the cyst fluid antigen of Cyticercus cellulosae for detecting Cag in serum and/or cerebrospinal fluid (CSF) of patients with neurocysticercosis or with other diseases. Results In the group of 82 cases of neurocysticercosis, the positive rate of serum Cag was 79.2% (65/82) and the positive rate of CSF Cag was 100% (26/26). After chemotherapy for 20 cases with positive serum Cag, the titer of serum Cag in 17 cases dropped to zero(85% ). Cag could not be detected in specimens from patients with other diseases. Conclusion These results indicate that the determination of Cag, especially of the CSF Cag, is useful for the diagnosis of neurocysticercosis and the drop in serum Cag is a good parameter for the evaluation of the effectiveness of chemotherapy.

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Animal Host of Schistosoma japonicum and Transmission of Schistosomiasis in Poyang Lake Region

Dandan LIN ; Yueming LIU ; Fei HU ; Shaoji ZHANG

Journal of Tropical Medicine.2003;3(4):383-387.

The article clarified, according to the recent research results which have been done in Poyang Lake region of Jiangxi province, bovines are the most important animal hosts of Schistosoma japonicum and infected bovines are main infectious sources of Schistosomiasis in Poyang Lake region. Spring (March to June) is the " cross transmission stage" between definitive host and intermediate host, that is, spring is not only the susceptible season of infection for livestock and human, but also is the susceptible season of infection for snails. In flood season (July to August), the transmission of Schistosomiasis between livestock and snails belong to " low level phase" . Autumn (September to Octber) is the second seasonal peak of cercariae and is the susceptible season of infection for livestock and human. Winter(November to Feburary in next year) is the non- susceptible season of infection. Most of the susceptible zones of infection for livestock, human and snails are the marshlands near the endemic villages.

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Primary Study of the Structure and Antigenic Epitopes of Antigen Pf332

Zhixin SHAN ; Xinbing YU ; Jin XU ; Zhongdao WU ; Xuerong LI ; Guowu BIAN ; Changling MA ; Yan LI ; Shouyi CHEN ; Xuchu HU

Journal of Tropical Medicine.2002;2(3):219-224.

Objective To understand the primary structure and potential antigenic epitopes of antigen Pf332(Ag332) of P.falciparum iso late FCC1/HN.Methods　Based on the published Pf332 gene sequence , nine pairs of primers were designed for the PCR amplification of the Pf332 gen e fragments from genomic DNA of P.falciparum isolate FCC1/HN. The amplified gene fragments were subcloned into pMD-18T vectors and sequenced. The sequences were aligned using DNAstar software to obtain the full-length sequence of the gene Pf332. The primary structure and sequence homology of Ag332 were analyzed by SAPS, Tmpred, SingalP and Blastn programs. Three fragments, R0, R1 and R2, cor responding to nt#9595-10083, nt#10339-10767 and nt#10855-11247 of Pf332 gene were subcloned into the eukaryotic expression vector pcDNA3-S separately. The Balb/c mice were immunized with pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3- S-R2 separately, and the expressions of the recombinant proteins were detected by immunohistochemistry assay. The protective immune responses elicited by DNA I mmunization were analyzed by ELISA and parasite growth inhibition tests in vitro .Results　Nine Pf332 gene fragments were specifically amplif ied, subcloned into pMD-18T vectors and sequenced. Pf332 gene of the P.falci parum isolate FCC1/HN was 16,377 bp in length, encoding a protein of 5,458 ami no acids, about 615.28kDa. The Ag332 contains 17 regions of highly degenerated Glu-rich repeats, with 30.18% Glu in total amino acids of Ag332. Ag332 of P.falciparum isolate FCC1/HN and 3D7 exhibited 94.55 % homology in amino acid residues. The results of immunohischemistry assay showed that R0, R1 and R2 were expressed in mice muscle tissue. The amount of IgG antibody of the groups immu nized with pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3-S-R2 were higher than those of blank and pcDNA3 groups (P＜0.05). The result of parasite growth inhibition test showed that the immunized sera at 1∶5 dilution of groups of pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3-S-R2 had an incomplete inhibitor y effect on P.falciparum growth. Conclusion　The antigen Pf332 is an large protein containing highly degenerated Glu-rich repeats. Pf332 gene fragments, R1 and R2 encoding potent antigenic epitope repeats.

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Molecular Cloning and Characterization of Two Hommologues of Yeast Sir2 Gene in the Parasitic Protist Trichomonas vaginalis

Yongmei SHI ; Yucai FU ; Mingyan XU ; Xiaoyuan XU ; Jinjie XU ; Tang PETRUS

Journal of Tropical Medicine.2007;7(4):297-302,306.

Objective To screen cell growth and senescence-related genes of the parasitic pmtist Trichomonas vaginalis,we launched an EST program and isolated two cDNA clones from a T.vaginalis cDNA library,which showed high homology in deduced amino acid sequences to yeast Sir2 and designated as TvSir2 and TvSir2-like.Method The cDNA sequence of TvSIR2 had a length of 1034 base pairs (bp) with an open reading frame of 915 bp,and TvSIR2-like,1214 bp with an open reading frame of 1116 bp.Result The two deduced amino acid sequences shared all the three conserved cole domains with yeast Sir2 and its homologues,suggesting that the two clones were Sir2 homologues. A cDNA fragment from each cDNA clone was subvloned into the expression vector pET-41a.The expression of the fusion proteins in E.coli BL21 stains was induced by isopropylthio-β-D-galactoside (IPTG).Two anti-sera were prepared by immunizing two guinea pigs with the purified fusion proteins, Western-blot analysis demonstrated that each anti-serum reacted with the corresponding recombinant protein and detected a clear band (TvSir2,34 000 Mr;TvSir2-like,42 000 Mr)in protein extracts of the protist.Immunofluolescence techniques showed that TvSir2 and TvSir2-like proteins were both localized in the legions of perinuelear (ER) and Golgi complex.Conclusion Our data suggest that TvSir2 and TvSir2-like were two members of Sir2 family.Their biological functions in the protist would be further studied.

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The genetic immunization in mice with three constructs of Toxoplasma gondii SAG1 gene

Xiaoguang CHEN ; Xiaohong ZHOU ; Ya GONG ; Peiliang YANG ; Shuman SHEN ; Mingchiu FONG ; Zhaorong LUN

Journal of Tropical Medicine.2001;1(1):3-9.

Three forms of the major surface antigen (SAG1)of Toxoplasma gondii, that is the membrane form, the secrete form and the intracellular form, were constructed and used to immunize BALB/c mice. The humoral response in the mice immunized with the membrane form and the secrete form of SAG1 appeared earlier and stronger than those mice immunized with the intracellular form. Result from the challenging infection demonstrated that the protection in the mice immunized with the membrane and the secrete forms was also stronger than in the mice immunized with the intracellular form. We suggest that the immune efficiency of the three forms of SAG1 in the mouse model is different.

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A New (2Fe-2S) Ferredoxin Gene from Trichomonas Vaginalis

Yucai FU ; Hong XU ; Jiaxin ZHANG ; Kehao ZHNAG ; Hong LIU ; Huirong LIN ; Xiaohong ZHENG

Journal of Tropical Medicine.2004;4(4):352-356,381.

Objectives The ferredoxins are iron-sulfur proteins, which function in electron transfer reactions in a variety of systems and participate in the activation of the antimicrobial agent metronidazole. The aim of this study is to clone and characterize ferredoxin genes of Trichomonas vaginalis. Methods A cDNA expression library was constructed with T. Vaginalis total RNA. Hundreds of cDNA clones were isolated and sequenced. Sequence analysis was performed using BLAST programs, ClustalW program, etc. Results One of the cDNA clones, which has homology with T.vaginalis ferredoxin, was further analyzed. This cDNA clone has an open reading frame of 312 base pairs. The deduced precursor protein contains 103 amino acid residues with a hydrogenosome targeting sequence (MLSQCSPLRF) at the N-terminal end. The primary sequence analysis revealed that this new ferredoxin (TvFd2) has a high homology (69% identity) to the previous reported T.vaginalis ferredoxin(TvFd). Interestingly, TvFd2 is homologous to both the two subclasses of (2Fe-2S) ferredoxins, the oxidase ferredoxins and the photosynthetic ferredoxins,but with low similarity. The conserved four-cysteine residues, which are predicted to form the iron-sulfur cluster,are arranged in a typical pattern of (2Fe-2S)ferredoxins(-C-X5-C-X2-C-Xn-C-). Conclusion These data show that TvFd2 is a putative new (2Fe-2S) ferredoxin of T.vaginalis. Its biological function remains to be studied.

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Regulation of Th1 and Th2 Type Cytokines in the NCC Patients Treated with Praziquantel

Yajie LI ; Weizhe ZHANG ; Xiaoli ZHANG ; Suqin MA

Journal of Tropical Medicine.2004;4(3):227-229,233.

Objective To explore immunological mark and the outcome of disease after pharmacological treatment in human NCC with praziquantel. Methods 35 patients were treated with praziquantel for 6 months. Levels of serum IL-2,IFN-γ, IL-12, IL-5, IL-10 and TNF-α were measured before and after treatment. Results Th1 type cytokines IL-2, IFN-γand IL-12 were up regulated after treatment( P ＜ 0. 01 ) . Levels of TNF-α and Th2 type cytokines IL-5 and IL-10 were remarkable decreased after treatment( P ＜ 0. 01 ). The levels of IL-2, IFN-γ and IL-12 from the patients with good response to the treatment is higher than those with no response to the treatment. Conclusion Th1 type cytokines were up regulated while Th2 type cytokines were down regulated in the NCC patients treated with praziquantel. The protective immunity may be related to the Thl cell activation.

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Expression of Hox Genes in Murine Brain by Human Cytomegalovirus Infection

Ni XIE ; Liyu CHEN ; Minhua LUO

Journal of Tropical Medicine.2007;7(5):408-411,417.

Objective To study the effect of of human cytomegalovirus (HCMV) infection on the expressions of Hox genes.Methods Forty eight kunming mice were randomly divided into infection group (n=32) injected with HCMVAD169 and control group (n=16) injected with saline into their brain.After 7,15,30,and 60 days,the cerebral lesions were observed by pathological method.HCMV antigen was detected by immunohistochemical method and HCMV DNA was detected by polymerase chain reaction (PCR). On the basis of developing HCMV mouse model. reverse trancriptase-polymerase chain reaction (RT-PCR) was applied to determine the expressions of Hox gene in the brains of infected mice.The expression of Hox genes were also analysed with Northern-blot by isotope labelled Hox genes oligonucleotide probes. Results A HCMV infection model was developed and extensive pathological damages in brain tissue of infected mice were observed.Meanwhile.the HCMV-LA and HCMV-DNA were also found in brain tissues of HCMV infected mice.The expression level of Hox genes in control and infected mouse brain were determined by RT-PCR and Northern-blot.RT-PCR and Northern-blot showed that mouse brain expressed Hox-A9,Hox-A10,Hox-A11,Hox-A12,and Hox-A13,but they did not express Hox-B13.After HCMV infection,murine brain was induced to express Hox-B13 gene(P＜0.01),and reached the peak at 30 d after infection.Comparing with the control group,the expression of Hox-A9 and Hox-A11 were down-regulated in infected group (P＜0.05);the expression of Hox-A10 and Hox-A13 were significantly higher in infected groups (P＜0.05).Conclusion The results suggest that HCMVAD169 is able to cause mouse CNS infection and induced the abnormal expressions of Hox genes. which provides more information for understanding the mechanism of congenital abnormal due to HCMV infection and a valuable method of clinical prevention and treatment of HCMV infection.

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A Novel Rabl-like Gene with A 25 bp Intron in Trichomonas vaginalis

Lili LUO ; Xiaoyuan XU ; Mingyan XU ; Yucai FU

Journal of Tropical Medicine.2008;8(7):633-638,648.

Objective The aim of this study is to clone and characterize a novel Trichomonas vaginalis Rabl-like geue (TvRabl-like) with a small intron. Methods The eDNA clone of TvRabl-like gene was isolated from a cDNA expression library and sequenced. Sequence analysis was performed using BLASTP, RPS-BLAST ClustalW programs.Phylogenetic analysis was carried out by MEGA3 program. The genomic DNA and mRNA of TvRab1-like gene were amplified using PCR and RT-PCR techniques respectively and also sequenced. Results The eDNA sequence of TvRab1-like gene had a length of 705 base pairs with an open reading frame of 603 bp. The deduced amino acid sequence from the open reading frame possessed 200 residuals corresponding to a putative M.W. 22532.2 and an estimated pl of 7.4. Sequence analysis demonstrated that TvRab1-like gene showed the highest homology to T. vaginalis Rabla (63% identity and 79% similarity) and the Rabl subfamily of other species, suggesting that the deduced amino acid sequence from this cDNA clone was a Rabl isoform. Phylogenetic analysis showed that TvRab1-like gene was clustered with T.vaginalis Rab1 subfamily in the phylogenetic tree. Sequencing of the PCR product of genomic DNA revealed that the genomic DNA possessed a 25 bp intron which contained canonical 5' GT-AG-3' and branch site motifs as those larger introns found in T.vaginalis and other eukaryotes. The analysis of RT-PCR products demonstrated the presence of the unspliced mRNA and spliced mRNA, indicating that there was a intron. Conclusion These data suggest that TvRabl-like gene belongs to T.vaginalis Rabl subfamily. TvRabl-like gene possesses a 25 bp splieeosomal intron which is the smallest one of the introns identified in this deepest-branching protist and might be the shortest intron of eukaryotes. Study of those introns might provide more insights into the intron evolution of eukaryotes.

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Induction of Apoptotic-like Cell Death in Trichomonas vaginalis by Metronidazole

Petrus TANG ; Chingcheng HUANG ; Jyhwei SHIN ; Renli ZHANG ; Juli LIU ; Yucai FU

Journal of Tropical Medicine.2007;7(9):837-841,849.

Objective Apoptosis or programmed cell death(PCD) has been studied extensively in multicellular organisms,however,very little is known about the molecular mechanisms by which apoptosis occurs in unicellular protozoan parasites.The aim of this study is to characterize the apoptosis or PCD of Trichomonas vaginalis induced by metronidazole (MTZ).Methods T. Vaginalis strain cultures were treated with various concentrations of MTZ and the number of viable cells were determined at different time intervals.The genomic DNA of MTZ treated T. Vaginalis was extracted and DNA fragmentation was analyzed.TUNEL assay was carried out to detect the endonuclease activity in T. Vaginalis after MTZ treatment.Flow cytometric analysis was used to analyse the phosphatidylserine (PS) exposure of T. Vaginalis.Results Metronidazole (MTZ) induced an apoptotic-like cell death in T. Vaginalis.This apoptotic-like cell death was demonstrated by cell shrinkage,phosphatidylserine exposure,and nuclear chromatin condensation.However, no oligonucleosmal DNA laddering was detected.Conclusion The regulatory pathway of apoptotic cell death in T. Vaginalis may be different from multicellular organisms.The determination of protozoan apoptotic pathways leading to cell death might ultimately allow the identification of new therapeutic targets.

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