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Browsing by Author "Frade, JP"

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  • Evaluation of the antiviral and antimicrobial activities of triterpenes isolated from Euphorbia segetalis
    Publication . Madureira, AM; Ascenso, JR; Valdeira, L; Duarte, A; Frade, JP; Freitas, G; Ferreira, MJU
    A phytochemical reinvestigation of the whole plant of Euphorbia segetalis yielded five tetracyclic triterpenes: 3 beta- hydroxy- cycloart- 25- en- 24- one ( 1), cycloart- 25- ene- 3 beta, 24- diol ( 2), cycloart- 23- ene- 3 beta, 25- diol ( 3), lanosta-7,9( 11), 24- trien- 3 beta- ol ( 4) and lanosta- 7,9( 11), 24( 31)- trien- 3 beta- ol ( 5). 3 beta- acetoxy- cycloart- 25- en- 24- one ( 1a) and glutinol ( 6), lupenone ( 7), dammaranodienol ( 9), cycloartenol acetate ( 10), 24- methylenecycloartanol acetate ( 11) and beta- sitosterol ( 12), isolated previously, were evaluated for their antiviral activities against Herpes simplex virus ( HSV) and African swine fever virus ( ASFV). Lupenone exhibited strong viral plaque inhibitory effect against HSV- 1 and HSV- 2. The in vitro antifungal and antibacterial activities of 1a, cycloart- 23- ene- 3 beta, 25- diol, 3- acetate ( 3a) and 6 - 12 were also investigated.
    2003Journal article Metadata only Show more
  • Rapid quantification of drug resistance gene expression in Candida albicans by reverse transcriptase LightCycler PCR and fluorescent probe hybridization
    Publication . Frade, JP; Warnock, DW; Arthington-Skaggs, BA
    We developed a rapid, sensitive, and reproducible assay to quantify Candida albicans ACT1, CDR1, CDR2, ERG1, and MDR1 mRNA using a two-step reverse transcription and LightCycler real-time PCR (RT-LightCycler PCR) method with sequence-specific hybridization probes. We compared RT-LightCycler PCR with Northern hybridization for quantitative analysis of gene expression in isolates with various fluconazole susceptibilities. Specificity of each LightCycler PCR was verified by LightCycler melting curve analysis and agarose gel electrophoresis of amplified products. Correlation of quantification results between RT-LightCycler PCR and Northern hybridization yielded correlation coefficients of greater than or equal to0.91 for all genes except MDR1 (0.74). In this case, reduced correlation was due to the inability of Northern hybridization to accurately quantify the high MDR1 expression in a susceptible dose-dependent isolate which was shown by RT-LightCycler PCR to overexpress MDR1 200-fold relative to the other isolates tested. In four isolates, low levels of CDR2 mRNA were detected by RT-LightCycler PCR but were undetectable by Northern hybridization. mRNA quantification by RT-LightCycler PCR correlates with Northern hybridization and offers additional advantages, including increased sensitivity and speed of analysis, along with lower RNA concentration requirements and an increased dynamic range of signal detection.
    2004Journal article Metadata only Show more