PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Aspergillus fumigatus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1986

Inhibition of complement by culture supernatants of Aspergillus fumigatus.

Aspergillus fumigatus produced a water-soluble extracellular material that inhibited the opsonization of fungal cells by normal human serum. Blastospores of Cryptococcus neoformans and conidia from A. fumigatus or Aspergillus niger were used as fungal targets for ingestion by human monocytes. The opsonic inhibitor from A. fumigatus was found to decrease binding of complement component C3b to fungal surfaces by selectively interfering with activation of the alternative complement pathway. Inhibition of complement did not appear to result simply from proteolysis, as judged by the minimal degradation of casein and of purified C3 and C4. The complement-inhibiting activity was partially labile to heating at 100 C and could be concentrated by using dialysis tubing with a 10,000-dalton exclusion limit. Aspergillus flavus, which is also a pathogen for humans, also produced this activity; A. niger did not. We speculate that this material may represent a pathogenesis factor for Aspergillus species.

Aspergillus fumigatus↗
PubMed1991

Isolation and characterisation of an extracellular alkaline protease of Aspergillus fumigatus.

Aspergillus fumigatus secreted an inducible alkaline protease (AlPase) when cultivated in the presence of collagen (200 micrograms/ml) as sole nitrogen and carbon source. Proteolytic activity was maximum at pH 9.0 with azocollagen as substrate. The enzyme, which was the major protein found in the supernate of a liquid culture, was purified by ammonium sulphate precipitation and gel filtration. The Mr was determined to be 33 Kda by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The isoelectric point was estimated to be pH 8.2. Divalent cations strongly inhibited enzyme activity, whereas non-ionic detergents and reducing agents had no effect. A. fumigatus AlPase was totally inhibited by phenylmethanesulphonyl fluoride, antipain, chymostatin and alpha-2-macroglobulin. A. fumigatus AlPase is closely related to the A. oryzae AlPase, a serine protease of the subtilisin family, as attested by the antigen pattern seen by immunoblotting. The high collagenic activity and the ability of A. fumigatus AlPase to digest elastin could play a role in the invasion of the tissues by the fungus.

Aspergillus fumigatus↗
PubMed2026

Functional characterization of SHC-like triterpene cyclase genes in azole response and virulence-related traits of Aspergillus fumigatus.

Aspergillus fumigatus is a major opportunistic fungal pathogen, and increasing azole resistance poses a challenge for aspergillosis treatment. Squalene is an upstream precursor of ergosterol biosynthesis and may also be utilized by SHC-like triterpene cyclases, suggesting a potential link between squalene-associated metabolism, membrane adaptation, and azole response. However, the roles of SHC-like triterpene cyclase genes in A. fumigatus remain unclear. Here, we characterized three candidates, shc1, shc2, and shc3, using comparative bioinformatic analysis, gene deletion, phenotypic assays, azole susceptibility testing, transcriptomics, and host-interaction models. Sequence, genomic-context, phylogenetic, and structural analyses suggested divergence among the three candidates. Individual shc deletion caused limited effects on vegetative growth, whereas loss of shc1 mildly reduced susceptibility to voriconazole and posaconazole, as reflected by twofold MIC increases and lower inhibition rates. Transcriptomic analysis revealed distinct remodeling patterns, with Δshc3 showing the broadest transcriptional changes despite no detectable MIC shift. Targeted metabolite profiling and PI uptake analysis further supported an association between shc deletion, sterol/hopane-type triterpenoid balance, and membrane-associated properties. shc deletion also altered epithelial cell interaction phenotypes, while Δshc1 showed reduced lethality in Galleria mellonella. In clinical isolates, elevated shc transcription was associated with azole-resistant backgrounds. These findings suggest functional diversification among SHC-like triterpene cyclase genes and indicate that shc1 may contribute to azole-associated adaptation and virulence-related traits in A. fumigatus.

Aspergillus fumigatus↗
PubMed1979

Effects of fungicides on Aspergillus fumigatus.

Aspergillus fumigatus was the most frequently isolated thermophilous fungus from green leaf surfaces. The application of fungicides significantly reduced the frequency of its occurrence there. A. fumigatus was relatively tolerant to fungicides. On Captan-, Thiram-, and Verdasan-treated leaves, A. fumigatus constituted 66%--80% of the total number of isolates obtained at 45 degrees C from each treatment while Dicloran did not depress the percentages. At 45 degrees C, A. fumigatus was found to be strongly cellulolytic with a slow rate of radial extension on YpSs agar and rapid rate of mycelial growth in Czapek Dox liquid medium. Increasing concentrations of all four fungicides reduced or prevented growth, sporulation, starch depletion and cellulose clearing of A. fumigatus. The fungus could tolerate higher concentrations of HgCl2 than of Verdasan. 2.5 microgram/ml of the four fungicides altered the rates of mycelial growth but not the maximum amount of mycelial dry weight attained.

Aspergillus fumigatus↗
PubMed1978

Aspergillus fumigatus and Aspergillus niger in two potted ornamental plants, cactus (Epiphyllum truncatum) and clivia (Clivia miniata). Biological and epidemiological aspects.

The presence and growth of Aspergillus fumigatus and Aspergillus niger in the soil of ornamental plants have been demonstrated. The ecological conditions in the soil of such plants as influenced by temperature, humidity, desiccation, fertilization and ventilation obviously influence such fungal growth. The epidemiological significance of these findings is of interest with a view to the present efforts to control aspergillosis in the environment of susceptible persons. Observations of a preferential growth of certain Aspergillus species in the soil of defined plants under defined conditions raise problems of soil microbiology.

Aspergillosis↗
PubMed1991

Two common fungi associated with farmer's lung: fine structure of Aspergillus fumigatus and Aspergillus umbrosus.

The fine structure of Aspergillus fumigatus and Aspergillus umbrosus by transmission electron microscopy (TEM) is described. The fine structure of the ascosporic and asexual stages of A. umbrosus is described for the first time. Dense, homogenous material and fibers were detected on the outer hyphal cell wall of the Aspergilli. Septal pores were found in the hypha of A. umbrosus. Two wall layers were detected in the cell wall of the conidia of the both Aspergilli. The ascospores of A. umbrosus contained thick cell wall and the surface of which was smoother than that of the conidia.

Aspergillus↗
PubMed1985

The action of itraconazole and ketoconazole on growth and sterol synthesis in Aspergillus fumigatus and Aspergillus niger.

Growth and sterol synthesis of Aspergillus fumigatus and A. niger were studied in control cultures and in the presence of ketoconazole or itraconazole, the latter compound being 100 times more growth inhibitory than the former. Sterol synthesis is inhibited more rapidly than any visible fungal outgrowth. This inhibition results in an accumulation of 4,14 dimethyl- and 4,4',14 trimethylsterols. The presence of these membrane-disturbing sterols may result in a pertubation of membrane-bound enzyme systems such as chitin synthase.

Aspergillus fumigatus↗
PubMed1992

Effect of methotrexate on the germination and growth of Aspergillus fumigatus and Aspergillus flavus strains.

Methotrexate at concentrations of greater than or equal to 10(-5) M caused a significant reduction in the rate of germ tube formation of spores of Aspergillus fumigatus, but not of Aspergillus flavus, after 7 h incubation. At 10(-3) M the drug caused a significant reduction in germ tube elongation of A. fumigatus and A. flavus strains during the first 7 h of germination. After 18 h incubation, drug concentrations of greater than or equal to 4 x 10(-4) M produced greater than 80% reduction in growth of all strains tested. Potentiation of the antifungal effect against A. fumigatus was detected in tests in which methotrexate at 10(-4) M was used in combination with amphotericin B at 5 x 10(-7) M.

Amphotericin B↗
PubMed1992

Nucleotide sequence of a genomic and a cDNA clone encoding an extracellular alkaline protease of Aspergillus fumigatus.

An Aspergillus fumigatus extracellular alkaline protease (ALP) which is an enzyme of the subtilisin family is a potential virulent factor of the fungus. The gene encoding ALP was isolated from a genomic library made from DNA of an A. fumigatus isolate. The nucleotide sequence of this gene was compared to that of a cDNA encoding A. oryzae ALP and to that of a cDNA from A. fumigatus encoding the mature ALP protein. Mature A. fumigatus ALP contains 282 amino acids and is encoded by three exons. The pre-proenzyme has a leader sequence of 121 amino acids.

Amino Acid Sequence↗
PubMed1985

Frequency of Aspergillus fumigatus isolates and antibodies to aspergillus antigens in cystic fibrosis.

The frequency of Aspergillus fumigatus isolates from sputum was assessed prospectively during a 22-month period in 156 patients with cystic fibrosis (CF) from one center, and findings were compared to a cross-sectional evaluation of specific IgG and IgA antibodies, occurrence of chronic Pseudomonas aeruginosa infection, and pulmonary function. The prevalence rate for the 22-month period was 40%. Positive A. fumigatus cultures appeared to be independent of the presence or duration of chronic bronchopulmonary Ps. aeruginosa infection, but isolation of A. fumigatus in patients with pseudomonas infection for more than 5 years was associated with notably decreased pulmonary function. Levels of IgG antibodies to a 470,000 daltons A. fumigatus antigen fraction were higher in patients with positive cultures in the observation period than in those without. IgG antibodies to a 25,000-50,000 daltons antigen fraction were directly correlated to A. fumigatus frequency in patients with positive cultures both prior to and during the survey. On the other hand, levels of IgA antibodies to the 470,000 daltons fraction were inversely related to A. fumigatus frequency, suggesting a role of IgA antibodies in the bronchial clearance of aspergilli. Decreased pulmonary function was found to be associated with elevated levels of A. fumigatus antibodies. It is concluded that immune reactions elicited by A. fumigatus may play a role in clearance of the fungus from the airways but also may contribute to lung morbidity in some patients.

Adolescent↗
PubMed1979

Characterization of antigens from Aspergillus fumigatus. III. Comparison of antigenic relationships of clinically important aspergilli.

Antigenic relationships between strains of Aspergillus fumigatus, Aspergillus fumigatus var. elipticus, Aspergillus phialiseptus, Aspergillus flavus, and Aspergillus niger were analyzed by fused rocket immunoelectrophoresis and by skin tests. Seventy-three to 89 % of the numbers of antigens detected between strains and species of the A. fumigatus series were shared. The degree of sharing between antigens of A. flavus, A. fumigatus series, and A. niger was much lower and ranged from 19 to 35 %. In reciprocal skin tests in sensitized guinea pigs, similar relationships were shown. Three fractions of A. fumigatus extract proved to be markedly specific for this species. Cross reactivity was associated primarily with carbohydrate and glycoprotein fractions.

Animals↗
PubMed1992

Application of ubiquinone systems and electrophoretic comparison of enzymes to identification of clinical isolates of Aspergillus fumigatus and several other species of Aspergillus.

The ubiquinone systems and electrophoretic comparison of enzymes were used to determine the relatedness among 64 isolates of seven Aspergillus spp. These were 31 clinical and 3 nonclinical isolates of Aspergillus fumigatus Fres., 2 isolates of A. nidulellus Samson & W. Gams, 8 isolates of A. terreus Thom, 4 isolates of A. flavus Link, 1 isolate of A. oryzae (Ahlburg) Cohn, 14 isolates of A. niger van Tieghem, and 1 isolate of A. japonicus Saito. The enzymes glucose 6-phosphate dehydrogenase, lactate dehydrogenase, glutamate dehydrogenase, fumarase, and malate dehydrogenase were examined. The relative mobilities were analyzed numerically. The results were presented as a dendrogram. Isolates from clinical and nonclinical sources within the same species had identical ubiquinone systems and identical or very similar enzyme patterns. In the dendrogram, 64 of the tested isolates were separated into seven major clusters at a 60% similarity level. Each major cluster corresponds to a single species. On the dendrogram, A. fumigatus isolates showed homogeneity, whereas A. niger isolates showed relative heterogeneity; in particular, A. niger MF-24 and the other A. niger isolates were distantly linked to each other. All A. fumigatus isolates had the Q-10 ubiquinone system and formed a single major cluster at a similarity level of 73% or greater. Glucose 6-phosphate dehydrogenase and glutamate dehydrogenase were key enzymes for differentiating all clinical and nonclinical isolates of A. fumigatus from the other Aspergillus spp. Ubiquinone systems and enzyme patterns appear to be objective and useful indicators for use in the precise identification of clinical isolates of Aspergillus spp.

Aspergillus↗
PubMed1991

Contribution to the prophylaxis of chicks aspergillosis: study of the contamination of a hatchery by Aspergillus fumigatus.

Contamination of a hatchery by Aspergillus fumigatus has been studied for 8 weeks from eggs to day old chicks. We have shown that the contamination of the hatchery originates on the egg shell and that each time the eggs are manipulated, spores of Aspergillus fumigatus are thrown into suspension in the air. Thus it seems necessary to bring eggs with as few as possible spores of Aspergillus fumigatus on their shell into the hatchery. Prophylaxis of aspergillosis should be foreseen from the conception of the hatchery: the ventilation system and the internal lay-out should be designed to prevent dispersion and accumulation of Aspergillus fumigatus spores during the processing of the eggs through the hatchery.

Air Microbiology↗
PubMed1975

Chitin assay used to demonstrate renal localization and cortisone-enhanced growth of Aspergillus fumigatus mycelium in mice.

Aspergillus fumigatus mycelium in untreated mice (N-mice) and cortisone acetate-treated mice (C-mice) has been quantified by chemical assay of fungal chitin. Cortisone pretreatment rendered mice more susceptible to infection by A. fumigatus (mean lethal dose at 20 days, congruent to 10(6) for N-mice; less than 10(4) for C-mice). In both N- and C-mice there was renal localization of mycelial infection at conidial doses less than the mean lethal dose. At a conidial dose greater than the mean lethal dose, mycelial infection was found in the kidneys and brain of N-mice and in the kidneys, liver, and heart of C-mice. Chitin assay results showed that A. fumigatus mycelium grew more rapidly in C-mice. It is suggested that the resistance of N-mice to mycelial development may be an important mechanism whereby natural resistance to A. fumigatus is conferred.

Animals↗
PubMed1986

Characterization of a major antigenic component of Aspergillus fumigatus.

A component of Aspergillus fumigatus, Ag 7, previously identified as a major antigen for patients with allergic bronchopulmonary aspergillosis, has been isolated by gel filtration and further purified by affinity chromatography using monospecific antiserum. The antigen, which binds both specific IgG and IgE antibodies, was shown to be a high molecular weight, 150-200 kD, heat-stable glycoprotein, which binds to concanavalin A, suggesting the presence of alpha-D mannopyrannoside, or alpha-D glucopyrannoside end residues. On sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) it had a subunit of molecular weight 36 kD (with or without prior reduction), which retained antigenicity and allergenicity when tested with patients' sera.

Animals↗
PubMed1990

Identification and partial characterization of diagnostically relevant antigens of Aspergillus fumigatus.

Metabolic antigens of Aspergillus fumigatus, soil strain 2605 and sputum isolate, were evaluated for their diagnostic applicability using hyperimmune sera and sera of adults and pediatric patients of allergic bronchopulmonary aspergillosis. An indirect ELISA was standardised by using 2-10 micrograms/ml of coating antigen for detection of specific IgG and IgE antibodies in the sera of patients. The ratios of absorbance for specific IgE and IgG antibodies by ELISA (normal to patients) were observed to be in the range of 1:2 to 1:3 to 1:8 respectively. These antigenic preparations were further analyzed to identify and characterize the individual components by immunoblotting. This analysis indicated the presence of allergenic and antigenic determinants in the antigens of molecular weights 70, 34, and 28 Kd. The utility of the antigens of soil strain for diagnostic purpose is suggested.

Adolescent↗
PubMedDate not supplied

Pathogenicity differences of multiple isolates of Aspergillus fumigatus in turkeys.

Sixteen Aspergillus fumigatus isolates of environmental, mammalian, and avian origin were used to assess: 1) intra-air-sac inoculation as a viable challenge alternative to aerosol exposure, and 2) isolate variability in pathogenicity. Development of lesions, antibody response in survivors, mortality, and weight gains were assessed. Turkey poults were challenged with equal numbers of viable conidia. Total number of conidia given per experimental group varied markedly and did not influence mortality. Antibody response as measured by the enzyme-linked immunosorbent assay and agar gel immunodiffusion test was erratic, although most poults with high antibody scores had marked lesions and low weight. Lesions were characterized by necrogranulomatous pneumonia and airsacculitis with marked visceral involvement. The source of the isolate was not a factor in mortality, although this was biased by the high numbers of isolates from birds with aspergillosis. The single environmental isolate produced no mortality.

Animals↗