Search results for "aspergillus"

Differential Expression of the Aspergillus fumigatus pksP Gene Detected In Vitro and In Vivo with Green Fluorescent Protein

2001

ABSTRACT Aspergillus fumigatus is an important pathogen of immunocompromised hosts, causing pneumonia and invasive disseminated disease with high mortality. To be able to analyze the expression of putative virulence-associated genes of A. fumigatus , the use of the enhanced green fluorescent protein (EGFP) as a reporter was established. Two 5′ sequences, containing the putative promoters of the pyrG gene, encoding orotidine-5′-phosphate decarboxylase, and the pksP gene, encoding a polyketide synthase involved in both pigment biosynthesis and virulence of A. fumigatus , were fused with the egfp gene. The P pksP - egfp construct was integrated via homologous recombination into the genomic pks…

Binding of human fibronectin to Aspergillus fumigatus conidia.

1996

Aspergillus fumigatus conidia exhibited the ability to bind purified human fibronectin, whereas mycelial forms did not bind the ligand, as detected by an indirect immunofluorescence assay with an antifibronectin polyclonal antibody after incubation of the cells with fibronectin. Flow cytometry confirmed that binding of the ligand to conidia was dose dependent and saturable. Pretreatment of the cells with trypsin markedly reduced binding, which suggested a protein nature for the binding sites present at the surface of conidia. Intact conidia were also able to adhere to fibronectin or antifibronectin antibodies, a significant reduction (from 88 to 92%) in the binding of conidia was noticed, t…

Binding of extracellular matrix proteins to Aspergillus fumigatus conidia

1996

As detected by confocal immunofluorescence microscopy, binding of fibronectin and laminin appeared to be associated with the protrusions present on the outer cell wall layer of resting Aspergillus fumigatus conidia. Flow cytometry confirmed that binding of laminin to conidia was dose dependent and saturable. Laminin binding was virtually eliminated in trypsin-treated organisms, thus suggesting the protein nature of the binding site. Conidia were also able to specifically adhere to laminin immobilized on microtiter plates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting) with laminin and antilaminin antibody of whole conidial homogenates allowed…

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…

Interaction of Human Phagocytes with Pigmentless Aspergillus Conidia

2000

ABSTRACT A defect in the pksP gene of Aspergillus fumigatus is associated with the loss of conidial pigmentation, a profound change of the conidial surface structure, and reduced virulence. The structural change of the conidial surface structure was not observed in similar A. nidulans wA mutants. Our data indicate that the pigment of both species is important for scavenging reactive oxygen species and for protection of conidia against oxidative damage.

Discovery of an Extended Austinoid Biosynthetic Pathway in Aspergillus calidoustus

2017

Filamentous fungi produce a wide range of natural products that are commonly used in various industrial contexts (e.g., pharmaceuticals and insecticides). Meroterpenoids are natural products of interest because of their various biological activities. Among the meroterpenoids, there is a group of insecticidal compounds known as the austinoids. These compounds have also been studied because of their intriguing spiro-lactone ring formation along with various modifications. Here, we present an extension of the original austinol/dehydroaustinol biosynthesis pathway from Aspergillus nidulans in the recently identified filamentous fungus Aspergillus calidoustus. Besides the discovery and elucidati…

Circumdatin H, a new inhibitor of mitochondrial NADH oxidase, from Aspergillus ochraceus

2005

Circumdatin H (1), a new alkaloid from the culture broth of Aspergillus ochraceus, has been isolated, together with a known circumdatin, circumdatin E (2) and other known compounds: flavacol (3) and stephacidin A (4). The structure of 1 was established on the basis of chemical and spectral evidence. All of these alkaloids showed biological activity as inhibitors of the mammalian mitochondrial respiratory chain.

Clinical risk factors for invasive aspergillosis in lung transplant recipients: Results of an international cohort study

2018

BACKGROUND: Invasive aspergillosis (IA) is a frequent complication in lung transplant recipients (LTRs). Clinical risk factors for IA have not been fully characterized, especially in the era of extensive anti-fungal prophylaxis. The primary objective of this study was to evaluate the clinical risk factors associated with IA in LTRs. The secondary objective was to assess the mortality in LTRs who had at least 1 episode of IA compared with LTRs who never had experienced IA.METHODS: We conducted an international, multicenter, retrospective cohort study of 900 consecutive adults who received lung transplants between 2005 and 2008 with 4years of follow-up. Risk factors associated with IA were id…

Pulmonary infiltrate with characteristic “reversed halo” and “air crescent” signs

2016

Toxicological Assessment of Recombinant Xylanase X22 in Wine

1999

Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wi…