Project description:We report a study conducted to investigate the variation on gene expression of the pathogenic fungus Aspergillus fumigatus upon co-cultivation with the pathogenic bacterium Pseudomonas aeruginosa. The study was conducted by investigating the gene expression variation at different time points (45, 90 and 180 minutes after co-incubation). As control, we used data obtained by cultivating the fungus either without bacteria, or with heat-inactivated Pseudomonas.
Project description:Dimethyl sulfoxide (DSMO) is a simple molecule widely used because of its great solvating ability. Beyond its physico-chemical properties, it is also biologically active, including on fungal species. Aspergillus flavus is a saprophytic and famous pathogenic fungus able to produce Aflatoxin B1 (AFB1), a potent carcinogenic mycotoxin which may contaminate many food crops. The aim of this study was to characterize the effect of DMSO on A. flavus transcriptome profile using high-throughput RNA-sequencing assay.
Project description:We examined the antifungal activity of artemisinin against Aspergillus fumigatus (A. fumigatus), a pathogenic filamentous fungus responsible for allergic and invasive aspergillosis in humans and analyzed transcript profiles of the fungus on exposure to Artemisinin. A. fumigatus spores were cultured for 48 h and then treated with artemisinin (at MIC50 concentration) or solvent control (DMSO) for 3 h to study its transcriptomic profiles.
Project description:The high demand for keratinolytic enzymes and the modest presentation of fungal keratinase diversity studies in scientific sources cause a significant interest in identifying new fungal strains of keratinase producers, isolating new enzymes and studying their properties. Four out of the 32 cultures showed a promising target activity on protein-containing agar plates-Aspergillus amstelodami A6, A. clavatus VKPM F-1593, A. ochraceus 247, and Cladosporium sphaerospermum 1779. The highest values of keratinolytic activity were demonstrated by extracellular proteins synthesized by Aspergillus clavatus VKPM F-1593 cultivated under submerged conditions on a medium containing milled chicken feathers. The enzyme complex preparation was obtained by protein precipitation from the culture liquid with ammonium sulfate, subsequent dialysis, and lyophilization. The fraction of a pure enzyme with keratinolytic activity (pI 9.3) was isolated by separating the extracellular proteins of A. clavatus VKPM F-1593 via isoelectric focusing. The studied keratinase was an alkaline subtilisin-like non-glycosylated protease active over a wide pH range with optimum keratinolysis at pH 8 and 50 °C.
Project description:Aspergillus flavus and A. oryzae represent two unique species predicted to have spent centuries in vastly different environments. A. flavus is an important opportunistic plant pathogen known for contaminating crops with the carcinogenic mycotoxin, aflatoxin and A. oryzae is a domesticated fungus used in food fermentations. Remarkably, the genomes of these two species are still nearly identical. We have used the recently sequenced genomes of A. oryzae RIB40 and A. flavus NRRL3357 along with array based comparative genome hybridization (CGH) as a tool to compare genomes across several strains of these two species. A comparison of three strains from each species by CGH revealed only 42 and 129 genes unique to A. flavus and A. oryzae, respectively. Further, only 709 genes were identified as being polymorphic between the species. Despite the high degree of similarity between these two species, correlation analysis among all data from the CGH arrays for all strains used in this study reveals a species split. However, this view of species demarcation becomes muddled when focused on only those genes for secondary metabolism.
Project description:Atomic force microscopy (AFM) imaging showed that the rodlet layer of A. fumigatus and A. flavus was different. The objective of this project was to examine the differences in the rodlet layer of these two pathogenic Aspergillus species.
Project description:N(5)-Carboxyaminoimidazole ribonucleotide synthetase (N(5)-CAIR synthetase), a key enzyme in microbial de novo purine biosynthesis, catalyzes the conversion of aminoimidazole ribonucleotide (AIR) to N(5)-CAIR. To date, this enzyme has been observed only in microorganisms, and thus, it represents an ideal target for antimicrobial drug development. Here we report the cloning, crystallization, and three-dimensional structural analysis of Aspergillus clavatus N(5)-CAIR synthetase solved in the presence of either Mg(2)ATP or MgADP and AIR. These structures, determined to 2.1 and 2.0 A, respectively, revealed that AIR binds in a pocket analogous to that observed for other ATP-grasp enzymes involved in purine metabolism. On the basis of these models, a site-directed mutagenesis study was subsequently conducted that focused on five amino acid residues located in the active site region of the enzyme. These investigations demonstrated that Asp 153 and Lys 353 play critical roles in catalysis without affecting substrate binding. All other mutations affected substrate binding and, in some instances, catalysis as well. Taken together, the structural and kinetic data presented here suggest a catalytic mechanism whereby Mg(2)ATP and bicarbonate first react to form the unstable intermediate carboxyphosphate. This intermediate subsequently decarboxylates to CO(2) and inorganic phosphate, and the amino group of AIR, through general base assistance by Asp 153, attacks CO(2) to form N(5)-CAIR.
Project description:Background and objectivesAspergillus clavatus antimicrobial peptide (AcAMP) is a fungi-derived peptide with a broad spectrum of activity against pathogenic bacteria and fungi. Natural antimicrobial peptides, including AcAMP, have attracted many attentions in the development of new natural antibiotics against pathogenic bacteria, especially multidrug resistant ones.Materials and methodsIn the present study, acamp gene was codon-optimized and chemically synthesized in pUC57 cloning vector, subcloned into pET28a (+) expression vector and transferred into competent Escherichia coli BL21 (DE3) cells. The expression of AcAMP was induced by addition of Isopropyl β- d-1-thiogalactopyranoside (IPTG) and the expressed peptide was purified by Ni-NTA. BALB/c mice were immunized with the purified peptide and the ability of the immunized mice sera for the detection of the native AcAMP secreted by A. clavatus IRAN 142C was examined through ELISA and Western blotting techniques.ResultsBoth ELISA and Western blotting demonstrated the ability of the sera of the immunized mice to detect the native AcAMP.ConclusionThe results of the present work show that the raised antibody against recombinant AcAMP can be used to detect AcAMP peptide, an issue which paves the way to develop detection kits for the detection of AcAMP-producing organisms, purification of this valuable peptide for further investigations.
Project description:Aspergillus terreus has been described as an allergenic fungus in addition to causing infection to both human beings and plants. However, the allergens in this fungus are still unknown. The identification of allergens is essential to develop diagnostic and therapeutic avenues. Employing a proteomic approach, sixteen allergens were identified based on two-dimensional immuno-blotting with A. terreus susceptible patient sera. Amongst them, triosephosphate isomerase (Asp t 36), one of the dominant immunoglobulin E (IgE)-reactive proteins, was purified under native conditions. To characterize Asp t 36, the gene was cloned and expressed in E. coli. Phylogenetic analysis showed it to be highly conserved with close similarity to Dermatophagoides farinae. Four immuno-dominant epitopes were identified using synthetic peptides and mapped on the tertiary structure of Asp t 36. Among these, two were found to create a continuous surface patch on the 3D structure rendering it to be an IgE binding hotspot. Asp t 36 showed similar secondary structure and temperature sensitivity with other reported triosephosphate isomerase allergens. In-vivo studies using the murine model demonstrated rAsp t 36 able to stimulate airway inflammation, such as an influx of eosinophils, goblet cell hyperplasia, elevated serum immunoglobulins and induction of Th2 cytokines. Collectively, our results reveal the immunogenic property of Asp t 36, a major allergen from A. terreus for the first time in any fungi. This allergen could serve as a potent candidate for investigating component resolved diagnosis and immunotherapy.