ABSTRACT
Objective:To evaluate the effect of microevolution on phenotypes and drug resistance of the Trichosporon asahii biofilm. Methods:The standard strain of Trichosporon asahii was obtained from the Fungal Biodiversity Institute of the Royal Netherlands Academy of Arts and Sciences, the fluconazole-sensitive primary strain (TO) of Trichosporon asahii was isolated from a case of trichosporonosis diagnosed in the Department of Dermatology, the Seventh Medical Center of Chinese People′s Liberation Army General Hospital in 2000, and the fluconazole-resistant evolved strain (TEVO) of Trichosporon asahii was isolated from the above patient in 2014. Biofilms of the above-mentioned strains were formed in vitro, and tetrazolium salt XTT reduction assay was performed to evaluate growth kinetics of the Trichosporon asahii biofilm, and laser scanning confocal microscopy to determine the thickness of the biofilm; the sessile minimum inhibitory concentrations (SMICs) of fluconazole, itraconazole and voriconazole against the biofilms at different growth stages were determined in vitro for the evaluation of the resistance of the biofilms. One-way analysis of variance was used for comparisons among multiple groups, and Hartley test for testing homogeneity of variance. If the variance was homogeneous, least significant difference test was used for multiple comparisons; if the variance was heterogeneous, Tamhane′ T2 test was used for multiple comparisons. Results:In the adhesion (0 h) and formation stages (4- 24 hours) of the Trichosporon asahii biofilm, the metabolic activity of the evolved strain TEVO was the weakest (adhesion stage: F = 35.705, P < 0.001; formation stage: F = 15.042, P < 0.001) . At 48 hours after adhesion, the biofilms matured, and the TO strain showed the weakest metabolic activity ( F = 10.985, P < 0.001) . In the maturation stage, the biofilm thickness of the TEVO strain (26.1 ± 1.18 μm) was significantly higher than that of the TO strain (22.8 ± 1.73 μm, P = 0.001) , but significantly lower than that of the standard strain (29.5 ± 1.28 μm, P = 0.001) . As drug susceptibility testing showed, the SMICs of azole antifungal agents against the TEVO strain were higher than those against the TO strain in the adhesion and formation stages of the Trichosporon asahii biofilm, and the SMICs of azole antifungal agents against the biofilms of the 3 strains of Trichosporon asahii were all over 1 024 mg/L in the maturation stage of the biofilm. Conclusion:Under the dual pressure of host environment and antifungal drugs, adaptive changes took place in the phenotypes of the Trichosporon asahii biofilm with an increase in the resistance to azole antifungal drugs.
ABSTRACT
Objective To investigate the effects of galectin-2, galectin-4, galectin-7, galectin-8, and galectin-9 on the apoptosis in HIV-1-infected macrophages and to provide the theoretical and application basis for elimination of HIV-1-infected cellular reservoirs. Methods Firstly, apoptosis of human monocytic cell line THP-1 cells was induced by different concentrations of galectins to determine the suitable concentration of different galetcins. Secondly, monocytes (THP-1) were stimulated to differentiate into macrophages (THP-1-Mφ) with phorbol myristate acetate (PMA), and then macrophages were prepared and infected with HIV-1. Finally, HIV-1-infected and uninfected macrophages were respectively treated with the suitable concentrations of galectin-2, galectin-4, galectin-7, galectin-8, galectin-9 and then the apoptosis in these macrophages was detected. Results The cell death rate of macrophages without treatment was 4. 39 ± 0. 74% . The cell death rates of macrophages induced by 5 μmol/L galectin-2, 5 μmol/L galectin-4, 7. 5 μmol/L galectin-7, 3 μmol/L galectin-8 and 1 μmol/L galectin-9 were 4. 78 ± 0. 41% , 7. 21 ± 1. 46% , 3. 78 ± 1. 03% , 5. 88 ± 2. 08% , 8. 10 ± 4. 13% , respectively, with no statistically significant defferences among the groups (P＞ 0. 05). The cell death rate of HIV-1-infected macrophages without treatment was 12. 69 ± 1. 16% , and that of HIV-1-infected macrophages induced by 5 μmol/L galectin-2, 5 μmol/L galectin-4, 7. 5 μmol/L galectin-7, 3 μmol/L galectin-8 and 1 μmol/L galectin-9 were 11. 69 ± 0. 90% , 17. 45 ± 1. 30% , 32. 01 ± 1. 30% , 15. 77 ± 1. 21% and 19. 27 ± 2. 13% , respectively. There were significant differences between the control group and galectin-7-treated group (P ＜ 0. 001 ). Conclusions Galectin-7-induces extensive apoptosis in HIV-1-infected macrophages but not in uninfected macrophages.