Transcriptomic analysis of the exit from dormancy of Aspergillus fumigatus conidia.

Background: Establishment of aspergillosis is depending upon the exit from dormancy and germination of the conidia of Aspergillus fumigatus in the lung. To gain an understanding of the molecular mechanisms underlying the early steps of conidial germination, we undertook a transcriptomic analysis using macroarrays constructed with PCR fragments from > 3,000 genes (around one third of the annotated A. fumigatus genome).

Recombinant antigens as diagnostic markers for aspergillosis.

Eight recombinant proteins and purified galactomannan of Aspergillus fumigatus were tested by enzyme-linked immunosorbent assay to quantify the anti-Aspergillus antibodies in sera of patients with aspergilloma, allergic bronchopulmonary aspergillosis (ABPA), and invasive aspergillosis (IA). In spite of the variability observed in the immune responses of individual patients, quantification of the antibody titers against the 18-kDa ribonuclease (RNU), the 360-kDa catalase (CAT), and the 88-kDa dipeptidylpeptidase V (DPPV) was useful for the diagnosis of aspergilloma and ABPA. Differential diagnosis of ABPA was even possible among cystic fibrosis as well as noncystic fibrosis patients.

Specific molecular features in the organization and biosynthesis of the cell wall of Aspergillus fumigatus.

The cell wall of Aspergillus fumigatus is composed of a branched beta1,3 glucan covalently bound to chitin, beta1,3, beta1,4 glucans, and galactomannan, that is embedded in an amorphous cement composed of alpha1,3 glucan, galactomannan and polygalactosamin. The mycelial cell wall of A. fumigatus is very different from the yeast Saccharomyces cerevisiae cell wall, and in particular lacks beta1,6 glucans and proteins covalently bound to cell wall polysaccharides.

Evidence for sexuality in the opportunistic fungal pathogen Aspergillus fumigatus.

Aspergillus fumigatus is a medically important opportunistic pathogen and a major cause of respiratory allergy. The species has long been considered an asexual organism. However, genome analysis has revealed the presence of genes associated with sexual reproduction, including a MAT-2 high-mobility group mating-type gene and genes for pheromone production and detection (Galagan et al.

Galactomannoproteins of Aspergillus fumigatus.

Galactofuranose-containing molecules have been repeatedly shown to be important antigens among human fungal pathogens, including Aspergillus fumigatus. Immunogenic galactofuran determinants have been poorly characterized chemically, however. We reported here the characterization of two glycoproteins of A.

Catalases of Aspergillus fumigatus.

Upon infection of a host, the pathogenic fungus Aspergillus fumigatus is attacked by the reactive oxygen species produced by phagocytic cells. Detoxification of hydrogen peroxide by catalases was proposed as a way to overcome this host response. A.

Conidial hydrophobins of Aspergillus fumigatus.

The surface of Aspergillus fumigatus conidia, the first structure recognized by the host immune system, is covered by rodlets. We report that this outer cell wall layer contains two hydrophobins, RodAp and RodBp, which are found as highly insoluble complexes. The RODA gene was previously characterized, and DeltarodA conidia do not display a rodlet layer (N.

A new experimental murine aspergillosis model to identify strains of Aspergillus fumigatus with reduced virulence.

Experimental animals are an obligate screen to investigate microorganism pathogenicity. Numerous animal models have been used to analyse the virulence of the opportunistic human pathogen Aspergillus fumigatus but none of the experimental models used previously have been satisfactory. This report discuss these models and presents a murine model of pulmonary aspergillosis that is very easy and the most adapted to compare the pathogenicity of A.

Characterization of a cell-wall acid phosphatase (PhoAp) in Aspergillus fumigatus.

In the filamentous fungus Aspergillus fumigatus, the vast majority of the cell-wall-associated proteins are secreted proteins that are in transit in the cell wall. These proteins can be solubilized by detergents and reducing agents. Incubation of a SDS/beta-mercaptoethanol-treated cell-wall extract with various recombinant enzymes that hydrolyse cell-wall polysaccharides resulted in the release of a unique protein in minute amounts only after incubation of the cell wall in the presence of 1,3-beta-glucanase.

Comparison of restriction fragment length polymorphism, microsatellite length polymorphism, and random amplification of polymorphic DNA analyses for fingerprinting Aspergillus fumigatus isolates.

Aspergillus fumigatus fingerprints generated by random amplification of polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) upon hybridization with repeated DNA sequences, and PCR detection of microsatellite length polymorphism (MLP) were compared among 67 isolates. In contrast to RAPD, RFLP and MLP gave discriminating and significantly concordant genotyping results.

Molecular diagnosis and epidemiology of fungal infections.

A variety of methods are utilized for DNA strain subtyping of Candida spp. because no 'gold standard' exists. Random amplified polymorphic DNA (RAPD) or restriction enzyme analysis (REA) are useful to determine the source of an outbreak, but more reproducible and discriminatory methods such as Southern hybridization and pulsed field gel electrophoresis (PFGE) may be required.

Molecular typing of environmental and patient isolates of Aspergillus fumigatus from various hospital settings.

Fingerprinting of more than 700 clinical and environmental isolates of Aspergillus fumigatus from four differential hospital settings was undertaken with a dispersed repeated DNA sequence. The analysis of the environmental isolates showed that the airborne A. fumigatus population is extremely diverse, with 85% of the strains being represented as a single genotype isolated once.

Longitudinal study of Aspergillus fumigatus strains isolated from cystic fibrosis patients.

The colonization over time of cystic fibrosis patients by Aspergillus fumigatus was investigated using a DNA fingerprinting method. Aspergillus fumigatus isolates collected sequentially for more than one year from six patients with cystic fibrosis were typed by Southern blot hybridization with a repetitive DNA sequence. Each cystic fibrosis patient harbored several strains of Aspergillus fumigatus that were isolated recurrently over time.

Cloning and disruption of the antigenic catalase gene of Aspergillus fumigatus.

Aspergillus fumigatus possesses two catalases (described as fast and slow on the basis of their electrophoretic mobility). The slow catalase has been recognized as a diagnostic antigen for aspergillosis in immunocompetent patients. The antigenic catalase has been purified.

Genetic diversity among clinical and environmental isolates of Aspergillus fumigatus.

To determine if cases of invasive aspergillosis (IA) were caused by strains of Aspergillus fumigatus with unique characteristics, strains from immunosuppressed patients with IA were compared to strains obtained from sputa of patients with cystic fibrosis and to strains from the environment. An extremely high genomic diversity was observed among the 879 strains typed by Southern blotting with a retrotransposon-like element from A. fumigatus (C.

Dipeptidyl-peptidase IV secreted by Aspergillus fumigatus, a fungus pathogenic to humans.

A dipeptidyl-peptidase IV was purified from the culture medium of the human-pathogenic fungus Aspergillus fumigatus. The enzyme has an apparent molecular mass of 95 kDa and contained approximately 10 kDa of N-linked carbohydrate. This glycoprotein is antigenic and has all characteristics of the class IV dipeptidyl-peptidases: removal of Xaa-Pro and to a lesser extent Xaa-Ala dipeptides from the N termini of peptides, including bioactive peptides such as neuropeptide Y, [des-Arg1] bradykinin, and glucagon-like peptide 1, activity at neutral pH, and presence in the amino acid sequence of the Gly-X-Ser-X-Gly consensus motif of the serine-hydrolases and the putative catalytic triad (Ser613, Asp690, His725) of the dipeptidyl-peptidases.

Biochemical and antigenic characterization of a new dipeptidyl-peptidase isolated from Aspergillus fumigatus.

A novel dipeptidyl-peptidase (DPP V) was purified from the culture medium of Aspergillus fumigatus. This is the first report of a secreted dipeptidyl-peptidase. The enzyme had a molecular mass of 88 kDa and contained approximately 9 kDa of N-linked carbohydrate.

A novel beta-(1-3)-glucanosyltransferase from the cell wall of Aspergillus fumigatus.

Cell wall transferases utilizing beta-(1-3)-glucan chains as substrates may play important roles in cell wall assembly and rearrangement, as beta-(1-3)-glucan is a major structural component of the cell wall of many fungi. A novel beta-(1-3)-glucanosyltransferase was purified to apparent homogenei ty from an autolysate of the cell wall of Aspergillus fumigatus. The enzyme had a molecular mass of 49 kDa and contained approximately 5 kDa of N-linked carbohydrate.

Attenuated virulence of uridine-uracil auxotrophs of Aspergillus fumigatus.

Aspergillus fumigatus mutants that are deficient in the de novo UMP biosynthesis pathway because of a mutation in the pyrG gene encoding orotidine-5'-phosphate decarboxylase (and therefore auxotrophic for uridine or uracil) were evaluated in a murine model of invasive aspergillosis. These mutants were entirely nonpathogenic, and mutant conidia remained ungerminated in alveolar macrophages. Both the germination and virulence defects could be restored by supplementing the drinking water of the animals with uridine.

Chemical and immunological characterization of the extracellular galactomannan of Aspergillus fumigatus.

The galactomannan (GM) produced extracellularly by Aspergillus fumigatus has been purified by a double sequential hydrazine-nitrous acid treatment of the ethanol precipitate of the culture filtrate. Nuclear magnetic resonance and gas-liquid chromatography-mass spectrometry analysis have been performed on intact GM, acid-hydrolyzed GM, and oligomers resulting from the acetolysis of the acid-hydrolyzed GM. Results show that A.

[Tools, progress and questions in the molecular study of Aspergillus fumigatus and invasive aspergillosis].

Development of A. fumigatus in the host tissues is due to the intrinsic biological characteristics of this fungus and to the impairment of the cellular defence reactions of the host. However, even today the understanding of the factors governing the infectivity of A.

Aspergillus fumigatus metalloproteinase that hydrolyses native collagen: purification by dye-binding chromatography.

A proteinase was purified from the human pathogenic fungus Aspergillus fumigatus. The four chromatographic steps, a "negative" dye column, a "positive" dye column, hydroxyapatite Ultrogel, and modified TSK gel (HW 55), gave a 14% overall yield. The protein migrated as a single band on SDS-PAGE and isoelectric focusing, with an M(r) of 82,000 and a pI of 5.

An 88-kilodalton antigen secreted by Aspergillus fumigatus.

An 88-kDa component secreted in vitro by Aspergillus fumigatus has been purified by sequential chromatographic procedures. The molecule is a glycoprotein with an N-linked sugar moiety composed of mannose glucose, and galactose (16:10:1). It is recognized by antibodies from patients with aspergilloma and has potential for the immunodiagnosis of aspergilloma.

Cell wall antigens in Aspergillus fumigatus.

The Aspergillus cell wall contains most of the antigens secreted by the fungus during its active in vitro or in vivo growth. These antigens, which bind to the IgE and IgG of allergic and aspergilloma patients or are secreted in the biological fluids of patients with invasive aspergillosis, are of primary importance in the diagnosis of aspergillosis. Located at the interface between host and pathogen cells, the fungal cell wall plays a major role during fungal invasion.

The 31 kd major allergen, Alt a I1563, of Alternaria alternata.

A component of Alternaria extract, previously identified as the major allergen, Alt a I1563, was purified to homogeneity from Alternaria mycelium by means of acetone precipitation and ion-exchange chromatography. The homogeneity of Alt a I1563 was assessed by one single band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by one single radiolabeled band after transfer to nitrocellulose, and by one single peak after size-exclusion chromatography by high-performance liquid chromatography. Alt a I1563 was isolated as a heat-stable acidic glycoprotein (carbohydrate content, 20%; pI, 4.