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Objective To study the role of cell density in the tyrosol production and morphology for Candida albicans biofilms. Methods C. albicans SC5314 and clinical isolates were propagated in yeast peptone dextrose (YPD) medium. Cells were collected by centrifugation and washed twice in sterile phosphate-buffered saline (PBS) before this study, then resuspended in RPMI 1640 supplemented with L-glutamine and adjusted to a desired concentration of 5 × 10~6 cells/ml, 5×10~5 cells/ml, 5 × 10~4 cells/ml, 5 × 10~3 cells/ml after counting with a hematocytometer. Standardized C. albicans cells were prepared as above description and 2000 μl of this standardized cell suspension was dispensed into the wells, then C. albicans biofilms were formed on the bottom of the polystyrene wells. In this study, tyrosol synthesized by SC5314 and clinical isolates of C. albicans biofilm was quantified by high performance liquid chromatography (HPLC). The effects of tyrosol on morphology of C. albicans biofilms were investigated by scanning electron microscopy (SEM). Results Tyrosol production of C. albicans biofilms was affected by cell densities. At lower inoculation size(5 μ 10~3 cells/ml), there was too less tyrosol production to be detected at the early stage of the biofilms formation. At higher inoculation size (5 μ10~6 cells/ml), tyrosol can be detectable at the early stage or at the mature stage of biofilms formation. There was a sharp increase in tyrosol concentration at 24 h, while there was a decrease in tyrosol concentration after that time from the strains when the strains were at an inoculation size of 5 × 10~6 cells/ml and 5 × 10~5 cells/ml. Cell densities affected the morphology formation of the C. albicans biofilms. At the early stage of the biofilms formation, C. albicans grew less germ tube at lower cell densities than that at the higher cell densities. With the mature of the biofilms, C. albicarts grew more hyphae at higher cell densities than that at the lower cell densities. All these above showed that cell densities played an important role in the propagation for the C. albi-cans in the biofilm formation. Conclusion Cell density play an important role in the formation of the C. albi-cans biofilms and the production of the tyrosol.
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Objective To investigate the immune response of IL-10 to Schistosoma japonicum infection in the early infectioin model and SEA immunization model of the IGTP~(-/-) and IRG-47~(-/-) mice.Methods In the early infection model,the IGTP knock out (IGTP~(-/-)) mice,IRG-47 knock out (IRG-47~(-/-)) mice and wild-type (WT) C57BL/6J mice were exposed to 300 S.japonicum cercariae via the pinna and sacrificed on day 7 post-infection.Each mouse pinna section was stained with hematoxylin-eosin (HE) to detect the pathological lesions,and the culture supernatant of pinna was used to test the levels of Th1/Th2 cytokines by indirect ELISA.In the SEA immunization model,IGTP~(-/-) IRG-47~(-/-) and WT mice were immunized with SEA twice and sacrificed in 3 weeks after the initial immunization.SEA-specific IgG antibody in sera was detected by indirect ELISA;the levels of Th1/Th2 cytokines were tested in culture supernatant of splenocytes by indirect ELISA;the proportions of CD4~+ T cells,CD8~+ T cells,B cells,Th1 and Th2 cells in the spleen were assayed by FACS.Results Although no obvious differences on the pathology of pinna were observed among the three mouse groups,the level of IL-10 in the culture supernatant of pinna of IRG-47~(-/-) mice was lower than that of IGTP~(-/-) mice in 7 days after the exposure.Following SEA immunization,the level of SEA-specific IgG antibody in sera of IGTP~(-/-) mice was lower than that in WT mice,the level of IL-10 in the culture supernatant of splenocytes of IRG-47~(-/-) mice was higher than that of IGTP~(-/-) and WT mice with the stimulation of SEA.However,the proportion of Th2 cells in the spleen of IRG47~(-/-) mice was the lowest among the three mouse groups.Conclusions SEA is the stimulus of IRG-47 deficiency mice to defend Schistosoma japanicum infection and promote the host to produce a protective response,and IL-10 may play an important role in immune regulation in this process.
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Objective To investigate the PCR-based evaluation of prednisolone-induced relapse of asymptomatic Toxoplasma gondii infection and the therapeutic efficacy of azithromycin.Methods A total of 36 of female ICR mice,about 20 g,were randomly divided into 6 groups:contrast group (C),prednisolone group (P),infection group(I),infection plus prednisolone group (IP),infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA).The infection group (I),infection plus prednisolone group(IP),infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA)were challenged at week 0 with 10 cysts of Toxoplasma gondii Prugniaud strain per injection intraperitoneally.The prcdnisolone group (P),infection plus prednisolone group (IP) infection plus prednisolone and azithromycin group (IPA)were injectied with prednisolone 1 mg into hind medial subcutaneous every day from the 6th week to 7th week.The infection plus azithromycin group(IA),infection plus prednisolone and azithromycin group (IPA) were injectied with azithromycin 250 mg/kg intraperitoneally every day from the 6th week to 7th week.The serum samples were collected and DNAs extracted at week 0,1,2,3,4,5,6 and 7 for amplification of Toxoplasma gondii of specific B1 gene by PCR.All the mice were sacrificed 7 weeks after the challenge to calculate the number of cysts in brain tissues.Results Compared with the primer of AF146527 gene,the primer of B1 gene was more sensitive and specific.The method of PCR could amplify the productions of specific B1 gene Toxoplasma gondii 5 weeks before the challenge,while it could not amplified 5 weeks after the challenge.All the mice of the IP group were dead 2 weeks after the injection of prednisolone (week 7),and the only two mice of the IPA group were dead at the same time (P <0.05),respectively.Compared with the I group,IA group and IPZ group,the number of cysts in brain tissues of the IP group significantly increased (P <0.01).Conclusions B1 as target gene is more suitable for diagnosis of Toxoplasma gondii infection by PCR.Prednisolone could induce the relapse of asymptomatic Toxoplasma gondii infection of mice and the mice are finally dead.Azithromycin is effective but it can not completely cure the Toxoplasma gondii infection.
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24 new cDNA sequences encoding cytochrome P450 were amplified respectively from deltamethrin susceptible and -resistant strains of the mosquito, Culex pipiens pallens, with a pair of degenerate primers according to the conservative amino acid sequences of CYP4 in insects by RT-PCR. Studies of molecular systematics show that the 24 new genes (alleles) belong to CYP4C, CYP4D, CYP4H and CYP4J subfamilies of the CYP4 family, and they were named by Cytochrome P450 Nomenclature Committee. Among the new genes (alleles), CYP4C23 may be a pseudogene, CYP4H13 has a retained intron 58 nucleotides in length, and CYP4J4V1 has a stop coden (TAG) in frame near the 3'-end.
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The authors,in this paper,has briefly looked back the developmental history of human parasitology,which,as an independent discipline,was established in late 19th century and early 20th century.In the process,it underwent an early height of development,then met with setback and relative decline.Since 70s-80s of last century,the introduction and application of new theory of modern biology,especially advanced biotechniques to parasitology has led to a striking development in many fields of the discipline,leading to deeper understanding of parasite-host interplay as well as providing new ideals and tools for disease control.The authors also stressed that nowadays the discipline is still relatively isolated from the mainstream of modern biologic research and is still neglected by scientific community and medical education in the world,though it still is one of the major problems in public health,particularly in developing world including China.To argue the currently neglected situation of parasitology,especially in medical education,the authors emphasized the continuing requirements for the discipline and reflected on the developmental strategy of parasitology to meet the coming challenges and opportunities for further development.
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Great progress has been made on vaccine research for schistosomiasis,including those on immune mec-hanism and Schistosoma genome which have made active effect to vaccine development.This paper reviews the progress on the candidate vaccine antigens including protein vaccine,DNA vaccine and multivalent vaccine against Schistosoma japonicum.
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In this study, antibody-dependent murine neutrophil-mediated cytotoxicity (ADCC)against schistosomula of Schistosoma japonicum (Chinese strain) were demonstrated in vitro by use of immune effector mechanism analysis system. The results showed that neutrophils from the normal mice could mediate the antibody-dependent ADCC reaction against the schistosomula of Schistosoma japonicum, This ADCC reaction was not dependent on the complements, the complements could not enhance the ADCC reaction mediated by the neutrophils.
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In this study the ability of the monoclonal anti-idiotypic antibody NP30 was tested as a substitute of diagnostic antigen in detecting antibody of Schistosoma japonicum from human sera by use of ELISA. The results showed that the seropositive rate was 98% with NP30 in the group of acute infection, which was comparable to 94% with gut associated antigens (GAA)and 98% with the soluble egg antigens (SEA); 87% with NP30 in the group of chronic infection which was comparable to 86% with GAA but lower than that of 98% with SEA. The false positive rate was about 3% for all three diagnostic antigens. The results also showed that the geometric mean titer (GMT) of antibody to NP30 was higher than that to GAA but lower than that to SEA in the acute infection group and the GMT of antibody to NP30 was lower than both those to GAA and to SEA in the chronic infection group,suggesting that the antibody to NP30 appeared earlier and decayed more quickly during the process of infection. The authors suggested that NP30 could be used for the diagnosis of schistosomiasis japonica.
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Eight murine monoclonal antibodies against surface determinants of Schistosoma japoni-cum (Chinese mainland strain) schistosomula were generated,of which only one monoclonal IgM antibody (N15D9) gave protection at level ranging from 14 to 39% in experiments of passive transfer or inhibition of infectivity while the others did not exhibit significant levels of passive protection.Further characterization of N15D9 antigen specificity showed that 96 and 14 kDa antigen molecules in cercaria,and 132 and 10 kDa in schistosomula could be recognized by N15D9 in Western blot assay.Furthermore,the 96 and 132 kDa molecules could also be recognized by pooled infected human sera while 14 kDa and 10 kDa only by sera from mice vaccinated with 3-hour schistosomula.The molecules recognizable by N15D9 were surface epitopes repeatedly expressed on cercaria,in vitro 3-hour mechanically transformed schistosomula and 5 day lung-stage schistosomula,as demonstrated by indirect immuno-fluorecence surface binding assay.