Search results for "Fungi Imperfecti"
showing 10 items of 78 documents
Recovery of mutants impaired in pathogenicity after transposition of Impala in Fusarium oxysporum f.sp. melonis
2000
The ability of transposon impala to inactivate genes involved in pathogenicity was tested in Fusarium oxysporum f. sp. melonis. Somatic excision of an impala copy inserted in the nitrate reductase-encoding niaD gene was positively selected through a phenotypic assay based on the restoration of nitrate reductase activity. Independent excision events were analyzed molecularly and shown to carry reinsertedimpala in more than 70% of the cases. Mapping of reinserted impala elements on large NotI-restriction fragments showed that impala transposes randomly. By screening 746 revertants on plants, a high proportion (3.5%) of mutants impaired in their pathogenic potential was recovered. According t…
Comparison of morphotypic and genotypic methods for strain delineation inCandida
1998
Summary. We compared two phenotypic methods, colony morphotyping on Sabouraud-tripheniltetrazolium agar (STTZ) and serotyping, with two genotypic methods, karyotyping and Random Amplified Polymorphic DNA bands obtained by PCR amplification (RAPD-PCR), for strain delineation in 33 Candida clinical isolates and two C. albicans strains from culture collections. Analysis of isolates on STTZ showed 11 different morphotypes. In two patients there was a switch in the morphotype coincidential with a change in the susceptibility of the isolates to azole antifungals. C. albicans isolates were divided into two serotypes. Sixteen and 18 different patterns were identified among the Candida isolates by k…
Growth and macromolecular content of the dimorphic fungus Aureobasidium pullulans and the effect of hydroxyurea and other inhibitors
1988
The growth kinetics and the macromolecular content of the yeast and ethanol-induced hyphal forms of Aureobasidium pullulans were studied. During the morphological transition from yeasts to hyphae, both the protein and RNA content decreased significantly, the mycelial form containing only 76% of the amount of protein in the yeasts, and 38% of the RNA. The DNA was the only component tested whose level increased during the transition. Among several compounds inhibiting macromolecular synthesis, only hydroxyurea showed a remarkable effect on the morphology of A. pullulans, inducing the mycelial morphology. The macromolecular composition of hydroxyurea-treated cultures changed with time in a way…
Isolation and characterization of a pigmentless-conidium mutant of Aspergillus fumigatus with altered conidial surface and reduced virulence.
1997
Aspergillus fumigatus is an important pathogen of immunocompromised hosts, causing pneumonia and invasive disseminated disease with high mortality. The factors contributing to the predominance of A. fumigatus as an opportunistic pathogen are largely unknown. Since the survival of conidia in the host is a prerequisite for establishing disease, we have been attempting to identify factors which are associated with conidia and, simultaneously, important for infection. Therefore, an A. fumigatus mutant strain (white [W]) lacking conidial pigmentation was isolated. Scanning electron microscopy revealed that conidia of the W mutant also differed in their surface morphology from those of the wild t…
Bioproduction of an extract from Penicillium funiculosum Thom with activity against Ceratitis capitata and Tetranychus urticae
1993
The bioproduction conditions of a crude extract from a strain of Penicillium funiculosum Thom, which shows activity against Ceratitis capitata and Tetranychus urticae, have been optimized. The efficacy degree was 95% (C. capitata) and 100% (T. urticae), according to Abbot. This is the first report on the pesticide activity of an extract from P. funiculosum against these species. The best yields were obtained when P. funiculosum was grown in Raulin-Thom medium at pH 6.5 with sucrose candy as the carbon source and ammonium sulphate and phosphate as the nitrogen source. Other favourable conditions were static cultures, at 28 degrees C, and in the dark.
Posaconazole against Candida glabrata Isolates with Various Susceptibilities to Fluconazole
2008
ABSTRACT We investigated the in vitro activities of posaconazole (POS), fluconazole (FLC), amphotericin B (AMB), and caspofungin (CAS) against four clinical isolates of Candida glabrata with various susceptibilities to FLC (FLC MICs ranging from 1.0 to >64 μg/ml). POS MICs ranged from ≤0.03 to 0.5 μg/ml; AMB MICs ranged from 0.25 to 2.0 μg/ml, while CAS MICs ranged from 0.03 to 0.25 μg/ml. When FLC MICs increased, so did POS MICs, although we did not observe any isolate with a POS MIC greater than 0.5 μg/ml. Time-kill experiments showed that POS, FLC, and CAS were fungistatic against all isolates, while AMB at eight times the MIC was fungicidal against three out of four isolates of C. gl…
Can the grey mould disease of the grape-vine be controlled by yeast?
2000
Botrytis cinerea has been found to be highly pathogenic to ‘Chardonnay’ and ‘Pinot noir’ cultivars of the grape-vine producing the characteristic grey mould symptoms within 7 days of inoculation to the vitro-plants. The yeast Pichia anomala (strain FY-102), isolated from apple skin, was found to be antagonistic to B. cinerea as it completely inhibited the appearance of the grey mould symptoms when grown together. The yeast was responsible for morphological changes such as coagulation and leakage of the cytoplasm of B. cinerea. The pathogen, when applied together with P. anomala, failed to bring about the grey mould symptoms on the grape-vine, suggesting that the yeast could control the expr…
In vitro fungicidal activities of echinocandins against Candida metapsilosis, C. orthopsilosis, and C. parapsilosis evaluated by time-kill studies.
2010
ABSTRACT Anidulafungin, micafungin, and caspofungin in vitro activities against Candida metapsilosis , C. orthopsilosis , and C. parapsilosis were evaluated by MICs and time-kill methods. All echinocandins showed lower MICs (mean MICs, 0.05 to 0.71 mg/liter) and the highest killing rates (−0.06 to −0.05 CFU/ml/h) for C. metapsilosis and C. orthopsilosis rather than for C. parapsilosis (mean MICs, 0.59 to 1.68 mg/liter). Micafungin and anidulafungin killing rates were greater than those determined for caspofungin. None of the echinocandins had fungicidal activity against C. parapsilosis .
Flow cytometric assay for estimating fungicidal activity of Amphotericin B in human serum
1992
We describe a simple and rapid bioassay for estimating fungicidal activity of Amphotericin B in human serum using flow cytometry. The method exploits the fact that Candida albicans damaged by Amphotericin B show a decrease in size and take up propidium iodide to exhibit a red fluorescence after deoxycholate treatment. These phenomena display characteristic dose dependencies, and their assessment permits serum fungicidal activity to be broadly grouped into three categories: (1) subfungicidal; (2) fungicidal; and (3) strongly fungicidal. In normal human serum, these three categories correspond to Amphotericin B concentrations of 0 less than or equal to 0.5 micrograms/ml, 0.75-1.5 micrograms/m…
Identification of Candida dubliniensis among oral yeast isolates from an Italian population of human immunodeficiency virus-infected (HIV+) subjects
2002
Candida dubliniensis, an emerging oral pathogen, phenotypically resembles Candida albicans so closely that it is easily misidentified as such. The aim of the present study was to evaluate the usefulness of two phenotypic methods, growth at 45 degrees C and 2,3,5-triphenyltetrazolium chloride (TTC) reduction, for confirming presumptive identification of C. dubliniensis and C. albicans by colony color on CHROMagar Candida (CAC) medium. A combination of these methods was used to establish the prevalence of oral C. dubliniensis in an Italian population of 45 human immunodeficiency virus (HIV)-infected subjects. Twenty-two samples (48.9%) were positive for yeasts on CAC medium producing a total …