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Objective To investigate the roles of Dectin-1 in phagocytosis of Candida albicans (C.albicans) by macrophage-like cells derived from a human acute monocytic leukemia cell line THP-1.Methods THP-1 macrophage-like cells served as the target cells,and were transfected with small interfering RNA (siRNA) targeting Dectin-1 to down-regulate the expression of Dectin-1 receptor (siRNA-Dectin-1 group).THP-1 macrophage-like cells transfected with nonsense siRNA (siRNA-NC) served as a negative control group.After transfection,the THP-1 macrophage-like cells in the above 2 groups were cocultured with heat-killed C.albicans separately.And then,fluorescence microscopy was performed to count THP-1 macrophage-like cells phagocytosing C.albicans,and flow cytometry was used to determine the mean fluorescence intensity (MFI) of dihydrorhodamine (DHR)-123 fluorescent cells.Statistical analysis was done by one-way analysis of variance (ANOVA) and t test with the SPSS19.0 software.Results After transfection with siRNA-Dectin-1,the mRNA and protein expression of Dectin-1 significantly decreased in THP-1 macrophage-like cells (t =26.163,P ＜ 0.001).After 1-,2-,4-hour co-culture of THP-1 macrophagelike cells with C.albicans,fluorescence microscopy showed that the phagocytosis rates of C.albicans by THP -1 macrophage-like cells were significantly lower in the siRNA-Dectin-1 group than in the negative control group (17.5％ vs.22.1％,18.6％ vs.24.3％,39.2％ vs.59.1％,respectively,all P ＜ 0.05),so were the percentage of THP-1 macrophage-like cells phagocytosing more than 3 C.albicans cells (2.2％ vs.4.7％,2.5％ vs.5.4％,5.1％ vs.8.3％,respectively,all P ＜ 0.05).After 30-minute,1-,2-and 4-hour co-culture of THP-1 macrophage-like cells with DHR-123-labelled C.albicans,flow cytometry showed that the MFI of C.albicans-phagocytosing cells was significantly lower in the siRNA-Dectin-1 group than in the negative control group (36.8 vs.45.7,54.3 vs.62.4,72.1 vs.84.9,93.6 vs.116.7,respectively,all P ＜ 0.05).Conclusion Dectin-1 receptor plays an important role in the phagocytosis of C.albicans by macrophages.
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Objective To evaluate effects of the yeast form of Sporothrix schenckii on activation of p38 mitogen-activated protein kinase (p38MAPK) and expression of interleukin-6 (IL-6) in macrophagelike THP-1 cells,which were differentiated from the human acute monocytic leukemia cell line THP-1.Methods THP-1 macrophage-like cells were divided into 3 groups to be treated with the yeast form of Sporothrix schenckii at a concentration of 2 × 106 colony-forming units (CFU)/ml (yeast form group),100 mg/L curdlan (curdlan group) and RPMI 1640 medium (blank control group) respectively.Real-time fluorescence-based quantitative PCR was performed to measure the mRNA expression of IL-6 in THP-1 macrophage-like cells in the above 3 groups after 3-and 6-hour treatment separately,and enzyme-linked immunosorbent assay (ELISA) to detect the level of IL-6 in the culture supernatant of THP-1 macrophagelike cells after 24-hour treatment.Western blot analysis was conducted to determine the protein expression of p38MAPK and phosphorylated p38MAPK (p-p38MAPK) in the above 3 groups after 30-and 60-minute treatment separately.Other THP-1 macrophage-like cells were pretreated with 100 nmol/L dexamcthasonc (a p38MAPK inhibitor) for 30 minutes,and then were divided into 3 groups to be treated with the yeast form of Sporothrix schenckii,curdlan and RPMI 1640 medium respectively,and changes in the level of pp38MAPK and mRNA expression of IL-6 were also detected.Statistical analysis was carried out with SPSS19.0 software by using one-way or multi-way analysis of variance and least significant difference (LSD) test.Results Significant differences in the mRNA expression of IL-6 in THP-1 macrophage-like cells were observed among the yeast form group,curdlan group and blank control group (F =5 552.22,P ＜0.001) after 3-hour treatment (56.81 ± 7.36,26.69 ± 1.22 and 0.97 ± 0.05,respectively) and 6-hour treatment (378.03 ± 16.67,276.24 ± 39.13 and 1.02 ± 0.04,respectively).Additionally,the yeast form group showed significantly higher mRNA expression of IL-6 after 6-hour treatment than that after 3-hour treatment (q =16.74,P ＜ 0.001).After 24-hour treatment,the level of IL-6 in the culture supernatant of THP-1 macrophage-like cells also significantly differed among the yeast form group,curdlan group and blank control group (59.96 ± 18.16 pg/L,91.01 ± 17.27 pg/L,5.50 ± 2.30 pg/L,respectively;F =26.62,P ＜ 0.01),and was significantly higher in the yeast form group than in the blank control group (P ＜ 0.01).After 30-and 60-minute treatment,the protein expression of p-p38MAPK was significantly higher in the yeast form group than in the blank control group (both P ＜ 0.01).Moreover,the mRNA expression of IL-6 (4.46 ± 1.03 vs.493.52 ± 113.87,P ＜ 0.001) and protein expression of p-p38MAPK (2.29 ± 0.37 vs.4.55 ±0.46,q =10.81,P ＜ 0.01) were both significantly lower in the yeast form group with dexamethasone pretreatment than in that without dexamethasone pretreatment.Conclusion In vitro treatment with the yeast form of Sporothrix schenckii can enhance the expression of IL-6 in human THP-1 macrophage-like cells by activating the p38MAPK signaling pathway.
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A 59?year?old female patient, who received bilateral lower limb amputation 39 years ago, presented with eczematoid changes in both lower limbs for over 20 years, and with chronic granuloma?like lesions complicated by verrucous hyperplasia for more than 10 years. There were large areas of infiltrative and proliferative lesions with exudation and peripheral erythema at the amputation sites in both knee joints. The lesions were hard with tenderness on palpation. Microscopic examination of lesional scales with 10%KOH showed negative results for fungi. However, three times of culture on the Sabouraud dextrose agar(SDA)medium all grew the same kind of fungus, and the front side and reverse side of its filamentous colony were white and orange yellow respectively. Microculture showed that linear hyaline conidiophores came out from lageniform mother cells with conidia ascending alongside. The conidia looked like dark brown eye lens, with an equatorial germ slit. Based on these findings, this fungus was identified as Arthrinium phaeospermum. Periodic acid?Schiff (PAS) staining showed scattered hyphae in the stratum corneum. The internal transcribe spacer(ITS)sequence of the isolated fungus showed 99%consistency with that of Arthrinium phaeospermum. The patient was diagnosed with cutaneous Arthrinium phaeospermum infection, and treated with oral itraconazole capsules 200 mg/d for 16 days. One month later, follow?up showed satisfactory outcomes.
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Objective To investigate the effects of Candida albicans on the expression of tumor necrosis factor-α(TNF-α)and activation of the intracellular signaling molecule p38 mitogen-activated protein kinase(p38MAPK)in a human acute monocytic leukemia cell line THP-1. Methods Some THP-1 cells were divided into several groups in vitro: two C. albicans groups treated with 105 CFU/ml and 106 CFU/ml heat-killed C. albicans respectively, a lipopolysaccharide (LPS)group treated with 100 μg/L LPS, a blank control group treated with RPMI 1640 medium, two dexamethasone-inhibited groups pretreated with 40 μg/L dexamethasone for 30 minutes followed by treatment with 106 CFU/ml heat-killed C. albicans and LPS respectively. After treatment for 1, 3 and 6 hours, real-time fluorescence-based quantitative PCR was performed to measure TNF-α mRNA expression in THP-1 cells in the above groups. Enzyme-linked immunosorbent assay(ELISA)was conducted to determine the level of TNF-α protein in the supernatant of THP-1 cells treated with 106 CFU/ml heat-killed C. albicans, 100 μg/L LPS or RPMI 1640 medium(blank control group)for 24 hours. Western blot was performed to measure the protein expression of p38MAPK and phosphorylated p38MAPK in THP-1 cells after treatment with 106 CFU/ml heat-killed C. albicans or RPMI 1640 medium (blank control group)for 30 and 60 minutes. Statistical analysis was carried out by using two-way analysis of variance, one-way analysis of variance and the least significant difference(LSD)-t test. Results Significant differences were observed in the mRNA expression level of TNF-α among the C. albicans groups, LPS group and blank control group (F = 110.98, P < 0.001). The mRNA expression level of TNF-α in THP-1 cells increased over time in a time-dependent manner after C. albicans treatment, with significant differences among different time points (F = 701.680, P < 0.001). Compared with the blank control group, both 106-CFU/ml C. albicans group and LPS group showed a significant increase in TNF-α protein expression (6385.70 ± 533.99 ng/L and 3212.06 ± 353.00 ng/L vs. 147.10 ± 0.53 ng/L, P < 0.001 and 0.005, respectively). An obvious increase was observed in the expression level of phosphorylated p38MAPK protein, but no significant changes were noted in that of p38MAPK protein, in THP-1 cells treated with 106 CFU/ml C. albicans for 30 and 60 minutes compared with the blank control group. The mRNA expression level of TNF-α significantly decreased in dexamethasone-pretreated 106-CFU/ml C. albicans group and LPS group compared with those without dexamethasone pretreatment(3.77 ± 0.62 vs. 208.50 ± 10.50, 6.20 ± 1.93 vs. 161.35 ± 1.65, both P < 0.001). Conclusions Heat-killed C. albicans can induce the activation of p38MAPK in and secretion of TNF-α by human THP-1 cells, which then participate in the innate immune response against C. albicans.
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Objective To investigate whether human neutrophils kill Candida albicans through recognition of insoluble β-glucan in cell walls of C.albicans (CalG) by dectin-1,a C-type lectin receptor.Methods Neutrophils were obtained from peripheral blood of healthy human subjects and cultured in vitro.Real-time PCR was carried out to quantify the mRNA expressions of dectin-1 and Toll-like receptor 2 (TLR2) in neutrophils challenged with CaIG of 100 mg/L for 1,6,and 24 hours.A Fluoro hydrogen peroxide (H2O2) detection kit was used to determine H2O2 levels in some neutrophils exposed to CaIG (100 mg/L) for 15 minutes,2 hours,6 hours,as well as in some neutrophils preincubated with laminarin (a dectin-1 inhibitor) of 100 mg/L and 50 mg/L for 30 minutes followed by challenge with CaIG of 100 mg/L for 2 hours.Colony forming units (CFUs) were counted after the incubation of C.albicans with neutrophils pretreated with laminarin of 100 mg/L and 50 mg/L for 30 minutes.Results The relative mRNA expression level of dectin-1 was 2.8195 + 0.1669,5.4859 + 0.7244 and 3.6041 + 0.5372 in neutrophils challenged with CaIG for 1,6 and 24 hours,respectively,significantly higher than that in unchallenged neutrophils at these corresponding time points (all P ＜ 0.01).The level of H2O2 was (64.55 + 15.67),(290.34 + 30.56),and (208.54 ± 26.88) μ mol/L respectively in neutrophils treated with CaIG for 15 minutes,2 hours,and 6 hours respectively,compared to (22.05 ± 3.99) μmol/L in untreated neutrophils (all P ＜ 0.01).The pretreatment with laminarin of 100 and 50 mg/L attenuated the release of H2O2 in CaIG-treated neutrophils by 73％ ((80.45 + 22.41) μ mol/L,P＜ 0.01) and 45％ ((130.42 + 44.55) μmol/L,P＜ 0.01),respectively,compared with neutrophils treated with CaIG only.The fungicidal activity of neutrophils against C.albicans was also significantly inhibited by pretreatment with laminarin of 50 and 100 mg/L (both P＜ 0.01).Conclusions Dectin-1 may be involved in the secretion of H2O2 as well as killing of C.albicans by human neutrophils,which may provide a preliminary evidence for adoptive transfer of neutrophils as an approach to the treatment of systemic C.albicans infection.
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Objective To evaluate the in vitro activity of seven imidazole antifungals against clinical isolates of common Candida species.Methods According to the Clinical and Laboratory Standards Institute (CLSI) microdilution method M27-A3,the in vitro activity of luliconazole,ketoconazole,miconazole,econazole,clotrimazole,sertaconazole and bifonazole was determined among 183 clinical isolates belonging to 5 species of Candida.Results The minimal inhibitory concentration range was 0.03-8 (geometric mean:0.067) mg/L for ketoconazole,0.03-16 (geometric mean:0.071 ) mg/L for miconazole,0.03-8 (geometric mean:0.207) mg/L for econazole,0.03-8 (geometric mean:0.061 ) mg/L for clotrimazole,0.03-16 (geometric mean:0.187) mg/L for sertaconazole and 0.03 -＞16 (geometric mean:1.050) mg/L for bifonazole. Luliconazole exhibited a superior activity against the 5 species of Candida in vitro,with the MIC range being 0.03-8 mg/L,geometric mean MIC 0.087 mg/L,MIC50 0.06 mg/L and MIC90 0.5 mg/L,respectively.However,some Candida isolates were identified to be relatively insensitive to these tested antifungals,including luliconazole.Conclusion All the tested imidazole antifungals,except for bifonazole,show an excellent activity against Candida species in vitro,but there exist a few Candida strains with relative insensitivity.
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A 19-year-old man was admitted to the hospital for erythema and nodules on the face and postauricular region for 6 years. Microscopic examination of lesion scrapings revealed brown septate hyphae. A restricted, velvety and black colony grew on Sabouraud's dextrose agar. Slide culture on potato dextrose agar plate showed flask-shaped phialides at the apex of or around the hyphae with clear collarettes and flaring apex,mucilage-encapsuled, round to oval, semi-endogenous phialosporae accumulating at the apex of the phialides,giving a flower-like appearance. Anti-fungal susceptibility test showed that the fungus was sensitive to itraconazole, terbinafine and amphotericin B, but resistant to fluconazole. Sequence analysis of the ITS1-ITS4 region revealed a 98% consistency with the reference sequence of ITS1-ITS4 of Phialophora verrucosa. On the basis of above findings, the patient was diagnosed with cutaneous phaeohyphomycosis. Clinical improvement was seen after treatment with oral itraconazole (400 mg/d).
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A 16-year-old woman presented plaques on the left auricle and face over a period of 3 years. Fungal culture grew black-grey or dust velvety colony on Sabouraud's dextrose agar plate. A slide culture on potato dextrose agar plate showed conidiophores which were unbranched or occasionally loosely branched. The conidia were sympodial, zero- to two- septate, with rounded apices and truncated bases. The optimum growth temperature was 26℃ - 30℃. The fungus had the ability to liquefy glutin and hydrolyze starch. Anti-fungal susceptibility test showed the fungus was susceptible to itraconazole, terbinafine and amphoterecin B, but resistant to fluconazole. Cutaneous biopsy specimens revealed brown hyphae and budding yeast cells. The sequence of internal transcribed spacer (ITS) 1-ITS4 region of the isolate rDNA was assessed and compared against the Genebank databases. A 99% consistence was observed in the ITS sequence between clinical isolate and reference strain of Veronaea botryose Ciferri et Momtemartini. Based on the above findings, the mold was identified as Veronaea botryose Ciferri et Momtemartini. The lesions gradually subsided after 8-month treatment with oral itraconazole of 100 mg twice daily.
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Objective To study the difference in pathogenicity and genotype between two isolates of Veronaeae botryosa with different temperature tolerance. Methods Two strains of Veronaeae botryose were isolated from two patients with phaeohyphomycosis in Jiangsu and Henan province respectively. Of them, the Jiangsu strain could grow well at 37 ℃, but Henan strain could not grow at 36 ℃. Eighty mice were equally classified into immunocompetent and immune-suppressed (induced by cyclophosphamide) groups to be inoculated with the two strains of Veronaeae botryosa respectively. Ten mice remained uninoculated and served as the control. The general condition, growth and organic involvement of mice were observed for 4 weeks followed by the killing of surviving mice. Homogenated tissue samples were obtained from liver, spleen, lung, kidney and brain; then, tissue culture, direct microscopy and pathological examination were performed. Genomie DNA was extracted from tissue samples and subjected to random amplified polymor-phic DNA (RAPD) analysis. PCR was performed to amplify the intemal transcribed spacer (ITS) of rDNA followed by sequencing Results Systemic phaeohyphomycosis was induced in both immunocompetent and immune-suppressed mice by the Jiangsu strain of Veronaeae botryose; the mortality was 30% in immune-competent mice and 65% in immune-suppressed mice with statistical significance between the two groups. In immune-suppressed mice inoculated with the Jiangsu strain, the infection rate was 100% in the lung,signifi-cantly higher than in other organs; on direct microscopy the infection rate reached 64.7% in the liver, and 70.5% on tissue culture. There was no significant difference in the infection rate among these organs in immunocompetent mice inoculated with the Jiangsu strain, with the infection rate being 57.8% in the lung and 42.1% in the liver. Increased infection rate was observed in the lung of immune-suppressed mice com-pared with immunocompetent mice (P < 0.05). No definite infection was seen in immunoeompetent or immune-suppressed mice innoculated with the Henan strain. RAPD analysis and sequencing revealed that there was a base variation (A/G) at position 236 of ITS gene between the two strains. Conclusions The two strains of Veronaeae botryosa have different genotypes. Systemic phaeohyphomycosis can be caused in immunocompetent and immuno-suppressed mice by the Veronaeae botryosa isolate from Jiangsu Province; the mortality was higher in immuno-suppressed mice than in immunocompetent mice. The pathogenicity of Veronaeae botryose is associated with the immune status of hosts. In immuno-suppressed mice, lung is the organ most susceptible to infection by Veronaeae botryosa.
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Objective To investigate the growth inhibition of Aspergillns fumigatus by Candida albicans in vitro and to develop the selective medium for clinical isolation of Aspergillus fumigatus.Methods Aspergillus fumigatus and Candida albicans were single or co-cultured in sabouraud dextrose agar(SDA) medium and SDA broth in dark at 25 ℃,and fungal growth,pigmentation,as well as colony diameter weredocumented.Results ①The sensitivity of culture of Aspergillus fumigatus and Candida albicans on SDAplate was 100CFU/ml.②The growth of 106CFU/ml and 103CFU/ml Aspergills fumigatus was completely inhibited by 106CFU/ml Candida albicans.③Growth inhibition of Aspergillus fumigatus was correlated with the concentration of Candida albicans.④SDA containing 1 mg/L fluconazole inhibited growth of Candida albicans,and no Candida albicans was detected on SDA containing 5 mg/L and 25 mg/L fluconazole.Growth of Aspergillus fumigatus was partially inhibited on SDA containing 25 mg/L fluconazole.Conclusions Candida albicans can inhibit the growth of Aspergillus fumigatus in vitro.SDA containing 5 mg/L fluconazole can be used as the selective medium for the isolation of Aspergillus fumigatus.
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Objective To investigate the relationship between the clinical manifestations,prognosis and histopathological findings of mucormycosis.Methods The clinical data on and pathological findings from 7 cases of mucormycosis confirmed by fungal culture in the institute from 1989 to 2006 were analyzed retrospectively.Results There was 1 case of hinocerebral mucormycosis and 6 cases of cutaneous mucormycosis,among them,2 were mucormycotic necrotizing fasciitis (MNF).The condition of patients with rhinocerebral mucormycosis or MNF aggravated rapidly and all the 3 patients died from mucormycosis. Histopathological examination showed mixed infiltrates of inflammatory cells as well as necrosis and angioin vasion.On the contrary,the condition of the remaining 4 patients with cutanesus mucormycosis,who presented mainly with indurated erythematous patch,progressed slowly,and 2 patients were cured.Histologically,the lesions were characterized by granulbmatous infiltration with a few hyphae;no typical angioinva sion phenomenon was noted.There was no evidence of perineural invasion with hyphae in any of the 7 cases.ConclusionIn patients with mucormycosis,histopathological findings characterized by mixed infiltrates of inflammatory cells,numerous hyphae and typical angioinvasion phenomenon may herald a poor prognosis.
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Objectives To develop a rapid genotyping method of clinical isolates of Malassezia from patients with tinea versicolor by PCR-RFLP,and to evaluate reliability of the approach as compared with biochemical classification.Methods Tween assimilation test and catalase reaction were carried out to identify 74 isolates of Malassezia species from patients with tinea versicolor and 7 Malassezia reference strains.The sequence of 28S rDNA of Malassezia species was amplified by PCR,and then the product was analyzed by RFLP with Eco88I,Bsp143Ⅱ and BshNⅠ,respectively.Results M.restricta,M.obtusa and M.pachydermatis were successfully identified by three restriction endonucleases.M.restricta was found to be more diverse from the other 6 species in genetic homology.By comparison with PCR-RFLP technique,a possible mistake was discovered with biochemical method.Conclusion PCR-RFLP is a promising molecular biological technique,which could rapidly and correctly classify Malassezia species.
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64 ?g/mL, turbinafine 0.125 ?g/mL, ketoconazole 4.0 ?g/mL, and miconazole 8.0 ?g/mL. Conclusion Based on the morphology of colony on SDA and the characteristic structures under the microscope, this is a case of subcutaneous infection caused by Arthrinium phaeospermum.