ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Investigation of the role of sterol Δ8 → 7-isomerase in the sensitivity of Saccharomyces cerevisiae to fenpropimorph (1994)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 122 (1994), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Treatment of Saccharomyces cerevisiae with the morpholine fungicide fenpropimorph was examined using both a wild-type and a mutant strain (erg2) defective in sterol Δ8 → 7-isomerase. No resistance to fenpropimorph was observed in the mutant strain after 3 days, although after 7 days the mutant and the wild-type strains had grown in concentrations of fenpropimorph close to the saturating dose. Re-inoculation of both strains into fresh medium containing fenpropimorph resulted in continued growth and this adaptation to fungicide tolerance was lost on subculture in the absence of fenpropimorph. Analysis of the sterols present in the cells indicated that fenpropimorph treatment resulted in the accumulation of Δ8,14-sterols. This accumulation and the corresponding depletion of ergosterol were correlated with growth inhibition rather than the presence of Δ8-sterols. Together with an absence of gene dosage effect for ERG2 on fenpropimorph sensitivity, this supports the hypothesis that sterol Δ8 → 7-isomerase inhibition does not contribute to the fungicidal activity of fenpropimorph.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1994.tb07171.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Studies on azole-induced cell death in Saccharomyces cerevisiae (1994)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 115 (1994), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The Saccharomyces cerevisiae strain XL16-5B exhibited a fungicidal response to treatment with ketoconazole. Cell death became apparent during prolonged treatment over 72 h following an initial period over 24 h where viable cells were found and limited cell division occurred. Sterol analysis showed some differences between XL16-5B and the strain XY729-5a, which had a fungistatic response to ketoconazole. In particular, the level of ergosterol was higher in XL16-5B and remained high during treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1994.tb06641.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Y132H substitution in Candida albicans sterol 14α-demethylase confers fluconazole resistance by preventing binding to haem (1999)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 180 (1999), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Fungal cytochrome P450 sterol 14α-demethylase (CYP51) is required for ergosterol biosynthesis and is the target for azole antifungal compounds. The amino acid substitution Y132H in CYP51 from clinical isolates of Candida albicans can cause fluconazole resistance by a novel change in the protein. Fluconazole binding to the mutant protein did not involve normal interaction with haem as shown by inducing a Type I spectral change. This contrasted to the wild-type protein where fluconazole inhibition was reflected in coordination to haem as a sixth ligand and where the typical Type II spectrum was obtained. The Y132H substitution occurred without drastic perturbation of the haem environment or activity allowing resistant mutants to produce ergosterol and retain fitness, an efficient strategy for resistance in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1999.tb08792.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Expression, purification, reconstitution and inhibition of Ustilago maydis sterol 14α-demethylase (CYP51; P45014DM) (1998)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 169 (1998), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Triadimenol and tebuconazole are potent inhibitors of the sterol 14α-demethylation reaction in fungi which is catalysed by CYP51, a haem-thiolate containing enzyme belonging to the cytochrome P450 monooxygenase superfamily. Using CYP51 from the phytopathogen Ustilago maydis, a comparison of the sensitivity of the fungal enzyme to triadimenol and tebuconazole has been carried out. U. maydis CYP51 was purified to homogeneity as determined by SDS-PAGE and specific haem content. Catalytic activity was investigated following reconstitution with its respective NADPH cytochrome P450 reductase and proposed endogenous substrate, 24-methylenedihydrolanosterol. Addition of the triadimenol and tebuconazole induced type II spectral changes in the enzyme, with saturation occurring at equimolar azole concentrations. Inhibition of reconstituted activities showed a one-to-one sensitivity of the fungal CYP51 as judged by IC50 values. The implications for fungicide mode of action and treatment are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1998.tb13342.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Bactericidal and inhibitory effects of azole antifungal compounds on Mycobacterium smegmatis (2000)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 192 (2000), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Azole antifungals are central to therapy and act by inhibiting a cytochrome P450, sterol 14-demethylase and blocking normal sterol synthesis. Our recent identification of a mycobacterial sterol biosynthetic pathway led us to probe the efficacy of a range of these compounds against Mycobacterium smegmatis. Several showed equivalent or greater inhibitory effects to those against Candida albicans, and bactericidal activity was demonstrated for four compounds, clotrimazole, econazole, miconazole and tebuconazole. The major drug used clinically, fluconazole, was ineffective. The results are discussed in the light of the world-wide spread of tuberculosis, including drug-resistant forms and the requirement for new drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2000.tb09375.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Molecular analysis of cyp51 from fluconazole-resistant Candida albicans strains (1997)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 151 (1997), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The target enzyme for fluconazole is sterol 14α-demethylase, a cytochrome P450 encoded by cyp51. One mechanism of fluconazole resistance likely to occur in Candida albicans is through an altered target site. To test this hypothesis DNA sequencing of the cyp51 coding sequence from 19 fluconazole-resistant and 19 fluconazole-sensitive C. albicans was undertaken. A number of point mutations were identified in the resistant isolates which were not present in the sensitive ones: F105L (five), E266D (five), K287R (one), G448G (one), G450E (one), G464S (three) and V488I (one). These alterations are discussed in the light of a molecular model of the enzyme regarding potential roles in resistance. It was also demonstrated that sequence-specific primers can be employed to identify polymorphisms which may be associated with resistance; diagnostic tests for resistant strains will prove of value in combating this serious clinical problem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1997.tb12580.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Evidence for cytochrome P-450 and P-450-mediated benzo(a) pyrene hydroxylation in the white rot fungus Phanerochaete chrysosporium (1996)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 135 (1996), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The presence of cytochrome P-450 and P-450-mediated benzo(a)pyrene hydroxylase activity in both microsomal and soluble fractions of the white rot fungus Phanerochaete chrysosporium was shown. The reduced carbon monoxide difference spectrum showed maxima at 448–450 and 452–454 nm for microsomal and cytosolic fractions, respectively. Both P-450 fractions produced a Type I substrate binding spectrum on addition of benzo(a)pyrene. Activity for benzo(a)pyrene hydroxylation was NADPH-dependent and inhibited by carbon monoxide. Km values for activity showed a difference between the cellular fractions with a Km of 89 μM for microsomal P-450 and 400 μM for cytosolic P-450. The Vmax values observed were 0.83 nmol min− (nmol microsomal P-450) −1 and 0.4 nmol min−1 (nmol cytosolic P-450)−1. The results indicate that P-450-mediated benzo(a)pyrene hydroxylase activity could play a role in xenobiotic transformation by this fungus beside the known ligninolytic exocellular enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1996.tb07965.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Defective sterol Δ5(6)desaturase as a cause of azole resistance in Ustilago maydis (1995)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 127 (1995), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Resistance to azole antifungals in Ustilago maydis was associated with a leaky defect in sterol Δ5(6)desaturase. This defect resulted in reduced accumulation of 14α-methylergosta-24(28)-diene-3β,6α-diol and an increase in the proportion of 14α-methylfecosterol in treated cells when compared to the parent strain. The results demonstrate the importance of this mechanism in pathogenic fungi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1995.tb07445.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Resistance to amphotericin B associated with defective sterol Δ8→7 isomerase in a Cryptococcus neoformans strain from an AIDS patient (1994)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 122 (1994), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Two Cryptococcus neoformans strains isolated from an AIDS patient were investigated, a pretreatment isolate (CN1) and a second isolate (CN3) following failure of fluconazole and amphotericin B treatment. No difference in fluconazole sensitivity, but relative resistance to amphotericin B was observed for CN3. The sterol composition of CN3 indicated a defect in sterol Δ8→7 isomerase in this strain and depletion of ergosterol, the major sterol of the CN1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1994.tb07140.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Biochemical characterisation of ketoconazole inhibitory action on Aspergillus fumigatus (1996)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS immunology and medical microbiology 16 (1996), S. 0 
    Details
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract The effect of ketoconazole on growth, sterol composition, in vitro sterol biosynthesis and P450-CO complex formation and its interaction with microsomal P450 was determined. On solid medium and in liquid medium ketoconazole inhibited Aspergillus fumigatus growth completely at 5 × 10−5 M and 50% of the growth at 1.3 × 10−5 M and 2.1 × 10−5 M respectively. A close relationship between accumulation of 14α-methyl sterols (eburicol, obtusifoliol and 14α-methyl fecosterol) and depletion of ergosterol with growth arrest was observed in ketoconazole treated cultures. The half inhibitory concentration for in vitro ergosterol biosynthesis and half saturating concentration for type II binding spectrum of ketoconazole were calculated as 73.8 ± 6.3 nM and 0.13 ± 0.04 μM respectively. CO displacement studies revealed inhibition of CO-P450 complex formation by ketoconazole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-695X.1996.tb00106.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...