[Investigation on spread and hazards of human parasites in Qushui Village, Suixi County, Zhanjiang City].

OBJECTIVE: To understand the transmission of human parasites in Qushui Village, Yangqing Town, Suixi County, Zhanjing City, Guangdong Province. METHODS: The direct stool smear, floatation, Kato-Katz technique, and hookworm larva culture were used for the parasite infections. The questionnaire survey was applied for the hazards of parasites. The dissections on rats and snails were used for Angiostrongylus cantonensis infection. RESULTS: Five parasites were found and the total infection rate was 10.75%. The infection rates of hookworm (Necator americanus), Ascaris lumbricoides and Trichuris trichiura were 6.07%, 1.87% and 1.87%, respectively, and the infection rates of Enterobius vermicularis and Tyroglyrhus farinae were both 0.47%. The infections were not correlated with the career and age but preferred to males. The densities of infections were slight. The rate of dermatitis caused by hookworm larvae was 69.23%. The infection rates of Angiostrongylus cantonensis were 16.66%, 13.04% and 10.00%, respectively in rats, Achatina fulica and Ampularum crossean. CONCLUSION: The main species of human parasites are nematodes, with hookworm predominately, in Qushui Village, Suixi County. This area is the natural foci of Angiostrongylus cantonensis.

[Subcellular mimical localization of the ATP synthase B subunit from Clonorchis sinensis under different conditions of cell cycling].

OBJECTIVE: To investigate the subcellular localization of ATP synthase b subunit from Clonorchis sinensis under different conditions of Hela cell cycling, and the effect of this protein on the expression of its encoding-gene and homologous host genes. METHODS: pEGFP-N1-CsATP-synt_B and the vector pEGFP-N1 were transfected into Hela cells, respectively. Transfected cells were synchronized in G0/G1 by serum starvation, G1/S, S cells by double thymidine block, and G2/M cells by thymidine-Nocodozale block. After synchronization, the subcellular localization of the expressed fusion protein was observed with a laser confocal microscope. The expression level of this fusion protein in cells was detected by flow cytometry (FCM). The expression of CsATP-synt_B and HomoATP-synt_B in different cell cycle phases accessed by RT-PCR. RESULTS: FCM results indicated that in the G0/G1 phase the expression of pEGFP-N1 vector was decreased significantly, while pEGFP-N1-CsATP-synt_B expression showed an upward trend. In the other phases of cell cycle, the protein expression was similar in the above two kinds of plasmids. The intact CsATP-synt_B was expressed in mitochondria in the G0/G1, S, and G2/M phases and nucleus during G1/S phase. After the fusion proteins entered the nucleus, the mRNA expression of CsATP-synt_B and HomoATP-synt_B increased significantly. CONCLUSION: CsATP-synt_B can be expressed in the nucleus during G1/S phase, and regulated by the cell cycle and energy requirements.

[Tissular and subcellular localization of the ATP synthase B subunit in Clonorchis sinensis].

OBJECTIVE: To illustrate the distribution of ATP synthase b subunit in the tissue of Clonorchis sinensis adult and its subcellular mimical localization in HeLa cells. METHODS: With the antiserum against recombinant CsATP-synt_B protein raised from SD rats as primary antibody, paraffin sections of the adult of C. sinensis were processed by the method of fluorescent immunohistochemistry to observe the distribution of CsATP-synt_B protein in adult worm. According to the prediction by bioinformatics of the definite mitochondrial targeting sequence (MTS) and probable Bipartite nuclear localization signals (NLS_BP)in CsATP-syntB sequence, recombinant pEGFP-N1 plasmids containing the intact and three defective CsATP-synt_B sequence with single defect of MTS or NLS_BP or double defect respectively were constructed. The recombinant plasmids and the control plasmid-pEGFP-N1, pEYFP-Mito and H2B-CFP, were transfected into the HeLa cells by Lipofectamine 2000 reagent and the subcellular location of the GFP fusion protein was observed with confocal microscopy. RESULTS: The CsATP-synt_B protein appeared to distribute all over the adult worm, especially abundant on the acetabulum, ovary, vitellarium and tegument. The intact CsATP-synt_B was definitely expressed in mitochondria and/or nucleus of infected HeLa cells, whereas the MTS-deleted mutant only in cytoplasma and nucleus, the NLS_BP-deleted mutant in mitochondria and cytoplasm, and the double defect mutant only in cytoplasm. CONCLUSION: The distribution of CsATP-synt_B in adult is accord with that of mitochondria, and mainly exits in the organs and the tissues of active energy metabolism. This study first predicted and confirmed that CsATP-synt_B can be expressed in the nucleus.

[Excretory/secretory antigens from Clonorchis sinensis induces hepatic fibrosis in rats].

OBJECTIVE: To investigate the role of excretory/secretory antigens from Clonorchis sinensis (CsESAs) in hepatic fibrosis induced by C. sinensis infection in rats and explore the possible mechanism. METHODS: CsESAs was collected from adult C. sinensis cultured in sterile condition for 12 h and injected intraperitoneally in Wistar rats. Masson staining was used to observe the changes in the hepatic collagen fiber after the injection. HE staining and immunofluorescence staining were performed to detect the expression of alpha-smooth muscle actin (alpha-SMA) to examine the proliferation and the activity of hepatic stellate cells. The specific antibody titer of CsESAs was determined using enzyme-linked immunosorbent assay to investigate the role of the antigen-antibody complex in the development of hepatic fibrosis. RESULTS: After intraperitoneal injection of CsESAs, obvious hepatic fibrosis and hepatic stellate cell proliferation and activation were observed in the rat livers. The severity of the hepatic fibrosis was associated with the dose of CsESAs injected, whereas the titer of the specific antibody against CsESAs showed no direct relation to the hepatic fibrosis. CONCLUSION: Intraperitoneal injection of CsESAs can cause hepatic stellate cell activation and hepatic fibrosis in rats, but the antigen-antibody complex does not seem to play the key role in the activation of the hepatic stellate cells.

[The effects of Lysophospholipase from Clonorchis sinensis on the hepatic stellate cells and oval cells of rat].

AIM: To clarify the effects of the recombinant protein of Lysophospholipase from Clonorchis sinensis (CsLysoPLA) on the hepatic stellate cells (HSC) and oval cells of rat. METHODS: Binding of the recombinant CslysoPLA protein to the membrane of HSC and oval cells was identified by immunofluorescent staining. The HSC and oval cells were cultured and treated with the recombinant protein at different doses, and proliferation was quantified by MTT method. Cell cycle analysis was performed by flow cytometry. RESULTS: The recombinant CslysoPLA protein could bind to the membrane of HSC and oval cells. Compared to control, 2 mg/L and 20 mg/L the recombinant protein could promote HSC and oval cells growth (P<0.05), whereas 200 mg/L the recombinant protein could induce the cells necrosis, which associated with overt plasma membrane disruption. Oval cell number in G(2) phase of the recombinant protein 20 mg/L treated group was higher than that of control group. CONCLUSION: In vitro, the recombinant protein could induce HSC and oval cells proliferation at low concentrations (2 mg/L and 20 mg/L), whereas it also could induce the cells necrosis at high concentration (200 mg/L). These results suggested that CslysoPLA might play a role in the pathogenicity of C. sinensis.

[Cloning and expression of the F0-ATP synthase B chain of Clonorchis sinensis and immunogenicity identification of the recombinant protein].

OBJECTIVE: To clone and express the Clonorchis sinensis F0-ATP synthase b chain (CsF0-ATP-synt_B) gene and analyze immunogenicity of the recombinant protein. METHODS: The coding region F0-ATP synthase b chain gene with the mitochondrial targeting sequence (MTS) removed was amplified with PCR using the cloned plasmid as template, and the product was cloned into the prokaryotic expression vector pET-28a(+), transformed into E. coli BL21 (DE3) and induced with IPTG. The expressed product was purified by Ni-IDA affinity chromatography,and analyzed by SDS-PAGE for its expression and identified by Western blotting for its immunogenicity. RESULTS: The coding sequence of the F0-ATP synthase b-chain like gene removed off the MTS contains 813 base pairs encoding 271 amino acids with a theoretical molecular weight of 31,171.9. PCR, double enzyme digestion and DNA sequencing confirmed that the recombinant plasmid pET-28a (+)-CsF0-ATP-synt_B was constructed successfully, and the resolvable expression was obtained in E.coli BL21. Highly purified recombinant protein was prepared through affinity chromatography. The recombinant protein could be recognized by the immune serum of the SD rat immunized with the recombinant protein. CONCLUSION: The CsF0-ATP-synt_B like gene has been efficiently expressed in prokaryotic expression system with immunogenicity.