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Objective To isolate and culture a clinical strain (GDI) of Treponema pallidum (Tp) in Guangdong province,and to investigate the difference in nonsynonymous single nucleotide polymorphisms (nsSNPs) between the GD1 strain and Tp Nichols strain.Methods The GD1 strain was isolated from the hard chancre in a patient with primary syphilis in Guangdong province,and continuously subcultured in the testes of New Zealand white rabbit.The serial subcultivation of GD1 was multi-verified by dark-field microscopy,polymerase chain reaction (PCR) for TP0548 gene,DNA sequencing and genotyping.Meglumine diatrizoate density gradient centrifugation was performed to isolate rabbit tissues and concentrate GD1,and DNA sequencing was used to verify the nsSNPs in the TP0443 and TP0584 genes.Results The GD1 strain was successfully isolated from the lesions of the patient with syphilis,and classified as a subtype f of TP0548.Compared with the American Tp (Nichols strain),there were nsSNP mutations in the GD1 strain.One mutation was located in the TP0443 gene,leading to the the substitution of threonine by alanine at amino acid position 120,and another one was located in the TP0584 gene,which caused a change from alanine to threonine at amino acid position 314.Conclusion The GD1 strain was successfully isolated firstly from the lesions in a patient with syphilis in Guangdong province,and nsSNP mutations were confirmed in the GD 1 strain on the etiology.
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Objective To evaluate the regulatory role of azithromycin-induced persistent Chlamydia trachomatis (Ct) infection in the apoptosis of Hela229 cells.Methods Hela229 cells were firstly co-cultured with Ct for 22 hours,and then cultured with Dulbecco's modified Eagle's medium (DMEM) containing 0.08 mg/L azithromycin for 26 hours to establish a cell model of persistent Ct infection (persistent infection group).These infected Hela229 cells cultured with azithromycin-free DMEM served as a cell model of acute Ct infection (acute infection group).After 48-hour infection with Ct,azithromycin was removed,and infected Hela229 cells in the above 2 groups were successively cultured with DMEM for the resurgence of Ct.Immunofluorescence assay and electron microscopy were performed to verify the persistent Ct infection model.The Hela229 cells in the persistent infection group and acute infection group as well as uninfected Hela229 cells (control group) were treated with staurosporine (STS) for 4 hours to induce the apoptosis,and then cell apoptosis was detected by Hoechst 33258 staining,annexin V/propidium iodide staining and flow cytometry.Results After the treatment with azithromycin,atypical inclusions with aberrant reticulate bodies appeared in the Ct-infected cells.After removing azithromycin,cells were cultured until 96 hours after infection,and infectious elementary bodies reappeared in the Ct inclusions.After the treatment with STS,Hoechst staining showed that there was loose chromatin in the persistently infected cells,while chromatin condensation was observed in the uninfected cells.After 24-hour infection with Ct and 4-hour induction with STS,the apoptosis rate was significantly higher in the persistent infection group (45.567％ ± 2.631％) than in the acute infection group (38.567％ ± 1.701％,t =2.686,P =0.028),but significantly lower in the persistent infection group than in the uninfected group (69.800％ ± 2.835％,t =8.187,P ＜ 0.001).After 48-hour infection with Ct and 4-hour induction with STS,there was a significant difference in the apoptosis rate between the persistent infection group (46.700％ ± 5.257％) and acute infection group (61.767％ ± 1.815％,t =5.781,P ＜ 0.001),as well as between the persistent infection group and the uninfected group (68.667％ ± 3.156％,t =7.421,P ＜ 0.001).Conclusion This study showed that azithromycin-induced persistent Ct infection regulated the apoptosis of host cells,and this effect lasted 48 hours.
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Objective To clone ,construction ,express and purify Tp47 of Treponema pallidum (Tp) ,and assess the immunoreac‐tivity by Western‐Blot .Methods Tp47 was amplified by polymerase chain reaction ,and then cloned to the vector pGEX‐6P‐1 .The correct sequence of the recombinant plasmids pGEX‐6P1‐Tp47 was transformed into Escherichia coli BL21 (DE3) and induced .The expression product was analyzed by sodium dodecyl sulfate polyacrylamide gel electropheresis and Western‐Blot .The expression protein was purified .Serum of different clinical stages of syphilis was used as the antibody to detect the immunoreactivity of the protein by Western‐Blot .Results A fusion protein with molecular weight about 71 × 103 was attained .Western‐Blot proved that the recombinant protein can react with Tp IgG positive sera .And the specificities and sensitivities of the diagnostic reagent detected by sera were 100% .Conclusion The recombinant protein Tp47 was expressed and purified with good antigen activity ,which could provide the basis of theory and practice for the development of early diagnostic kit applying to detect Tp infection .
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Objective To trace changes in the transcript level of the Treponema pallidum(Tp)protein Tp0751 in skin lesions of a rabbit model of early syphilis. Methods Three New Zealand white rabbits were intracutaneously injected with 0.1 ml of Tp (Nichols Seattle strains)suspensions (107 treponemes/ml)at 10 sites on the shaved back to establish a model of early syphilis. All the rabbits received a single injection with the total amount of treponemes being 107. Then, skin changes at injection sites were observed, and the size of skin rashes was recorded on a daily basis. Skin specimens sized 0.4 cm × 0.4 cm were excised from an injection site and a non-injection site(negative control)separately every 3 days for the detection of Tp0751 and Tp0574 mRNAs. The whole experiment lasted 30 days, and a total of 11 skin biopsies were carried out. Fluorescence-based quantitative PCR was performed to measure the mRNA expressions of Tp0751 and Tp0574 continuously and dynamically during the development of chancre. Results After intracutaneous injection of Tp suspensions, red papules occurred on the back of rabbits on day 6, and reached maximum size on day 19 with the formation of ulcer and chancre. On day 25, disseminated secondary syphilides gradually appeared all over the body surface of the rabbits. The mRNA expression levels of Tp0574 and Tp0751 increased at the early stage, peaked onday 15 (compared with the other time points, all P < 0.05), thereafter rapidly declined, but rose slightly on day 27. The standardized expression level of Tp0751 mRNA increased gradually after day 15, and peaked on day 24 (compared with the other time points, all P < 0.05). Conclusion The transcript level of Tp0751 was high in rabbits at the late stage of Tp clearance when generalized disseminated secondary syphilides had not appeared, suggesting that Tp0751 may be involved in the systemic spread of Tp.
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Objective To determine the frequency of T helper type 22 (Th22) cells and expression level of interleukin-22 (IL-22) in peripheral blood of patients with psoriasis vulgaris,and to investigate their relationship with disease severity and clinical course.Methods Peripheral blood samples were obtained from 40 patients with psoriasis vulgaris and 30 healthy human controls.Five-color flow cytometry was performed to determine the percentage of Th22 cells in peripheral blood,and enzyme-linked immunosorbent assay (ELISA) to measure the expression of serum IL-22.Statistical analysis was carried out by t test and Pearson correlation analysis.Results Both the percentage of Th22 cells and serum level of IL-22 in peripheral blood were significantly higher in patients with psoriasis vulgaris than in healthy human controls (Th22 cells:0.65％ ± 0.48％ vs.0.33％ ± 0.15％,t =3.89,P ＜ 0.01; IL-22:(67.96 ± 14.32) vs.(40.59 ± 9.91) ng/L,t =9.45,P ＜ 0.01).Further more,Th22 cell percentage and IL-22 serum level in peripheral blood were both positively correlated with psoriasis area and severity index (PASI) in these patients (r =0.38,0.94,P ＜ 0.05 and 0.01,respectively),but neither of them correlated with clinical course of psoriasis vulgaris (r =0.20,0.10,respectively,both P ＞ 0.05).Conclusions The percentage of Th22 cells and level of IL-22 are increased in peripheral blood of patients with psoriasis vulgaris,and both of them are correlated with disease severity.
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ObjectiveTo establish a mouse model for genital tract infection with different serovars of Chlamydia trachomatis(Ct),and to provide a basis for understanding the relationship between Ct serovars and virulence.MethodsSix-week-old female BALB/c mice were divided into 4 groups:study group (pretreated with progesterone and inoculated with 4.0 × 107 inclusion-forming units(IFU) of Ct serovar E,F,J and K,respectively),progesterone-control group(pretreated with progesterone and inoculated with culture medium of McCoy cells),non progesterone-control group(inoculated with 4.0 × 107 IFU of Ct serovar F),blank control group receiving no treatment.At 4 and 7 days after the inoculation,the appearance of vulva was observed,vaginal swab specimens were obtained and subjected to cell culture,direct immunofluorescence assay and real-time fluorescence-based PCR for the detection of Ct.ResultsA slight inflammation of the genital tract was observed in the mice 4 days after the inoculation with Ct serovar E,F,J or K in the study group.Cell culture,direct immunofluorescence assay and real-time fluorescence-based PCR all confirmed that Ct was present in vaginal specimens from the study group,but absent from the control groups.The longest duration of infection was 21 days in 1 out of 11 mice inoculated with Ct serovar K,followed by 17 days in 1 out of 11 mice inoculated with Ct serovar J,14 days in 5 out of 11 mice with Ct serovar F and in 2 out of 11 mice with Ct serovar K.Conclusion The model for genital tract infection with different serovars of Ct can be established in mice at a right age bypretreatment with progesterone and inoculation with a certain amount of Ct.
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Objective To assess the vitro susceptibility to 6 antimicrobial agents and genotypes of clinical isolates of Chlamydia trachomatis (Ct) from Guangzhou region. Methods Ct was isolated from clinical specimens by using McCoy cell culture and subjected to propagation. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of 6 antimicrobial agents (clarithromycin, roxithromycin, azithromycin, doxycycline, tetracycline, ofloxacin) against Ct isolates were determined in McCoy cell culture. Nested PCR was performed to amplify the outer membrane protein 1 (omp1) VS1-2 gene followed by sequencing. Results Seventy-six Ct strains were isolated from 346 urogenital specimens, and 40 strains met the require ments for susceptibility testing after serial propagation. The MIC50/MIC90 of clarithromycin, azithromycin, roxi thromycin, doxycycline, tetracycline and ofloxacin were as follows: 0.008/0.032, 0.080/0.160, 0.125/0.500, 0.032/0.064, 0.250/0.500 and 0.500/1.000 mg/L. Seven genotypes were observed. The most prevalent geno types in decreasing order were E (14, 35%), J (10, 25%)and F (6, 15%). The MIC50 was consistent for azithromycin among the 7 genotypes, but varied by 1 - 4 folds for doxycycline, ofloxacin and roxithromycin. Conclusions Clarithromycin, doxycycline and azithromycin exhibit an excellent activity against Ct, and the activity of azithromycin is consistent among the 7 genotypes of Ct.
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Objective To develop a PCR-mverse dot blot hybridization(RDB)assay to rapidly detect pathogenic mycoplasmas in genitourinary tract.Methods Universal primers were designed and applied to amplify the 16S rRNA gone of ureaplasma parvum(Up),ureaplasma urealyticum(Uu),Mycoplasma genitalium(Mg),Mycoplasma hominis(Mh)by using nestcd PCR.Specific nucleotide probes of Up,Uu,Mg and Mh Were constructed and immobilized onto nylon membranes.PCR products were denatured and hybridized、with specific oligonucleofide probes on nylon membrane.The sensitivity and specificity of the PCR-RDB assay were evaluated based.on the hybddizafion results.Also,PCR-RDB Was utilized to detect pathogenic mycoplasmas from 60 clinical samples.Results The four probes selectively hybridized with the PCR product of corresponding mycoplasmas,and no cross hybridization was observed.The detection limit of PCR-RDB Was one colony forming unit(CFU)of mycoplasma.Out of the 60 clinical samples、19were positive for mycoplasm,Mixed infections were found in three samples,including two coinfected with Up and Uu and one with Uu and Mg.Conclusion PCR-RDB is a rapid,specific and sensitive approach to the identification of pathogenic mycoplasmas in urogenital tract.