Browsing by Author "Lo, Hsiu Jung"

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Cph1p negatively regulates MDR1 involved in drug resistance in Candida albicans
(2015-06-01)
Lo, Hsiu Jung
;
Tseng, Kuo-Yun
;
Kao, Yeong-Yi
;
Tsao, Ming-Yang
;
Lo, Han-Lun
The cph1/cph1 efg1/efg1 double mutant in Candida albicans is defective in filamentous growth and is avirulent in a mouse model. We previously reported that Efg1p but not Cph1p is involved in drug resistance by negatively regulating ERG3 in C. albicans. In the current study, we have found that overexpression of 0411 in Saccharomyces cerevisiae increases susceptibility to the antifungal drug fluconazole. Furthermore, in C. albicans, null mutation of 0411 increased the expression of MDR1 as well as decreased susceptibility to fluconazole and voriconazole but not to amphotericin B. These findings indicate that although Efg1p and Cph1p may have the same effects on virulence, they have opposite effects on drug resistance in C. albicans. (C) 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
R432 is a key residue for the multiple functions of Ndt80p in Candida albicans
(2012-03-01)
Yang, Yun Liang
;
Wang, Chih Wei
;
Leaw, Shiang Ning
;
Chang, Te Pin
;
Wang, I. Chin
Ndt80p is an important transcription modulator to various stress-response genes in Candida albicans, the most common human fungal pathogen in systemic infections. We found that Ndt80p directly regulated its target genes, such as YHB1, via the mid-sporulation element (MSE). Furthermore, the ndt80 (R432A) allele, with a reduced capability to bind MSE, failed to complement the defects caused by null mutations of NDT80. Thus, the R432 residue in the Ndt80p DNA-binding domain is involved in all tested functions, including cell separation, drug resistance, nitric oxide inactivation, germ tube formation, hyphal growth, and virulence. Hence, the importance of the R432 residue suggests a novel approach for designing new antifungal drugs by blocking the interaction between Ndt80p and its targets.
Susceptibilities to Amphotericin B, Fluconazole and Voriconazole of Trichosporon Clinical Isolates
(2012-08-01)
Tsai, Moan Shane
;
Yang, Yun Liang
;
Wang, An Huei
;
Wang, Lih Shinn
;
Lu, Daniel C. T.
A total of 35 Trichosporon isolates were collected from the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) project from 1999 to 2006, and their identifications as well as drug susceptibilities were determined. The most frequently isolated species was T. asahii (62.9%), and the most common clinical sample that yielded Trichosporon isolates was urine (37.1%). The etiology of all seven invasive trichosporonosis was T. asahii. For the 22 T. asahii isolates, the MIC50 and MIC90 for amphotericin B were 0.25 and 1 mu g/mL, respectively. Those for fluconazole were 2 and 4 mu g/mL, respectively, and for voriconazole 0.031 and 0.063 mu g/mL, respectively. When the intraclass correlation coefficients (ICCs) and agreements were calculated, we found that the MICs of fluconazole obtained from different methods were similar and the inter-method discrepancies were low. Nevertheless, no unanimous MIC of amphotericin B and voriconazole was obtained among different methods.
"Susceptibilities to Amphotericin B, Fluconazole and Voriconazole of Trichosporon Clinical Isolates"
(2012-08-01)
Tsai, Moan Shane
;
Yang, Yun Liang
;
Wang, An Huei
;
Wang, Lih Shinn
;
Lu, Daniel C. T.
"A total of 35 Trichosporon isolates were collected from the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) project from 1999 to 2006, and their identifications as well as drug susceptibilities were determined. The most frequently isolated species was T. asahii (62.9%), and the most common clinical sample that yielded Trichosporon isolates was urine (37.1%). The etiology of all seven invasive trichosporonosis was T. asahii. For the 22 T. asahii isolates, the MIC50 and MIC90 for amphotericin B were 0.25 and 1 mu g/mL, respectively. Those for fluconazole were 2 and 4 mu g/mL, respectively, and for voriconazole 0.031 and 0.063 mu g/mL, respectively. When the intraclass correlation coefficients (ICCs) and agreements were calculated, we found that the MICs of fluconazole obtained from different methods were similar and the inter-method discrepancies were low. Nevertheless, no unanimous MIC of amphotericin B and voriconazole was obtained among different methods."