Search results for "aspergillus"
showing 10 items of 221 documents
Multiplex Detection of Aspergillus Species
2016
Multiplex real-time polymerase chain reaction (PCR) provides a fast and accurate DNA-based tool for the simultaneous amplification of more than one target sequence in a single reaction. Here a duplex real-time PCR assay is described for the simultaneous detection of Aspergillus carbonarius and members of the Aspergillus niger aggregate, which are the main responsible species for ochratoxin A (OTA) contamination in grapes. This single tube reaction targets the beta-ketosynthase and the acyl transferase domains of the polyketide synthase of A. carbonarius and the A. niger aggregate, respectively.Besides, a rapid and efficient fungi DNA extraction procedure is described suitable to be applied …
Toxicity reduction of ochratoxin A by lactic acid bacteria.
2017
Abstract Ochratoxin A (OTA) is a mycotoxin produced by the metabolism of fungus belonging to the genus Aspergillus and Penicillium. In this paper we report, the capacity of different cultures of lactic acid bacteria (LAB) to degrade OTA present in MRS broth at both pH 3.5 and 6.5. A study of OTA reduction during gastrointestinal digestion carried out with the LAB was also performed. Taking into account the two reduction mechanisms of OTA studied in this work as the enzymatic one and the adsorption on the cell wall, as well as at pH 3.5 and 6.5 the reduction values of OTA were in a range of 30–99%, being the strains with greater reduction (97% and 95%) Lb. rhamnosus CECT 278T and Lb. plantar…
Devices containing allyl isothiocyanate against the growth of spoilage and mycotoxigenic fungi in mozzarella cheese
2018
Filter paper and stickers containing allyl isothiocyanate (AIT), as well as pouches containing mustard meal and water for intrinsic production of AIT, were tested against aflatoxigenic strains of Penicillium digitatum CECT 2954 and Aspergillus parasiticus CECT 2681 in sliced mozzarella. Slices were inoculated with either fungus, packaged in plastic bags or plastic trays with one antimicrobial device (2–16 µL/L of AIT). Control groups presented visual growth of P. digitatum after 19.0 ± 1.5 d in bags and 26.1 ± 2.1 d in trays. A. parasiticus was visually detectable after 41.4 ± 1.7 d and 28.4 ± 1.5 d in trays and bags, respectively. AIT‐treated samples did not present visual fungal growth fo…
Antimicrobial packaging based on ɛ-polylysine bioactive film for the control of mycotoxigenic fungi in vitro and in bread
2017
Abstract ɛ‐Poly‐l‐lysine (ɛ‐PL) is a cationic peptide with a broad‐spectrum antimicrobial activity. This study investigates the use of ɛ‐PL as natural antimicrobial to inhibit fungal growth and to reduce aflatoxins (AFs) production. Antifungal activity of starch biofilms with different concentrations of ɛ‐Poly‐l‐lysine (ɛ‐PL) was determined in solid medium against Aspergillus parasiticus (AFs producer) and Penicillium expansum. Then, biofilms were tested as antimicrobial devices for the preservation of bread loaf inoculated with A. parasiticus CECT 2681 and P. expansum CECT 2278. Shelf life and AFs content were examined. Biofilms with concentrations of ɛ‐PL less than 1.6 mg/cm2 showed no fu…
Inoculation of airborne conidia of Penicillium chrysogenum on the surface of a solid medium
2016
International audience; To reproduce a fungal contamination of food products by airborne conidia, a method to inoculate a few number (in the range 1-9) of conidia on the surface of agar media was developed. This technique would allow to determine accurately the time to detection of fungal colonies, then the mould free shelf-life of food products by using dry conidia. The method was based on dry-harvesting the conidia in the lid by gently taping the bottom of the dishes where sporulating mycelium was grown, retaining the conidia on glass beads, and, aseptically transferring the beads to successive Petri dishes to "dilute" the samples. Among the eleven factors tested by means of an experiment…
Modelling the effect of temperature, pH, water activity, and organic acids on the germination time of Penicillium camemberti and Penicillium roquefor…
2017
International audience; In this study, the influence of environmental factors on the germination time of Penicillium camemberti and Penicillium roqueforti conidia was evaluated. To do so, the effects of i/temperature, pH, water activity, and ii/organic acids were determined using models based on i/cardinal values, and ii/minimum inhibitory concentration (MIC) respectively. Cardinal values for germination of conidia were not observed to be species dependent. Minimum temperatures were estimated to be below the freezing point, with an optimum of 26.9 degrees C, and a maximum of 33.5 degrees C. For both species, minimal and optimal a(w) values were found to be 0.83 and 0.99, respectively, while…
Nanoparticle decoration impacts airborne fungal pathobiology
2018
Airborne fungal pathogens, predominantly Aspergillus fumigatus, can cause severe respiratory tract diseases. Here we show that in environments, fungal spores can already be decorated with nanoparticles. Using representative controlled nanoparticle models, we demonstrate that various nanoparticles, but not microparticles, rapidly and stably associate with spores, without specific functionalization. Nanoparticle-spore complex formation was enhanced by small nanoparticle size rather than by material, charge, or "stealth" modifications and was concentration-dependently reduced by the formation of environmental or physiological biomolecule coronas. Assembly of nanoparticle-spore surface hybrid s…
Biopreservation potential of lactic acid bacteria from Andean fermented food of vegetal origin
2017
Abstract Microbial fermentations have long represented a way of natural biopreservation of raw materials, which frequently originated new food products. Among them, traditionally fermented products still manufactured by native populations all around the world are source of lactic acid bacteria (LAB) strains with high biotechnological potential. LAB are food grade microorganisms and therefore a good alternative to chemicals to be applied in food preservation. A total of 130 LAB isolates recovered from “chicha” and “tocosh”, traditional fermented Andean products of vegetal origin, were screened for antimicrobial activities against spoiler fungi Meyerozyma guilliermondii CECT 1021 (synonym Pic…
Characterization of sulfhydryl oxidase from Aspergillus tubingensis
2017
Background Despite of the presence of sulfhydryl oxidases (SOXs) in the secretomes of industrially relevant organisms and their many potential applications, only few of these enzymes have been biochemically characterized. In addition, basic functions of most of the SOX enzymes reported so far are not fully understood. In particular, the physiological role of secreted fungal SOXs is unclear. Results The recently identified SOX from Aspergillus tubingensis (AtSOX) was produced, purified and characterized in the present work. AtSOX had a pH optimum of 6.5, and showed a good pH stability retaining more than 80% of the initial activity in a pH range 4-8.5 within 20 h. More than 70% of the initia…
Polymorphisms within the ARNT2 and CX3CR1 Genes Are Associated with the Risk of Developing Invasive Aspergillosis.
2020
Invasive aspergillosis (IA) is a life-threatening infection that affects an increasing number of patients undergoing chemotherapy or allo-transplantation, and recent studies have shown that genetic factors contribute to disease susceptibility. In this two-stage, population-based, case-control study, we evaluated whether 7 potentially functional single nucleotide polymorphisms (SNPs) within the ARNT2 and CX3CR1 genes influence the risk of IA in high-risk hematological patients. We genotyped selected SNPs in a cohort of 500 hematological patients (103 of those had been diagnosed with proven or probable IA), and we evaluated their association with the risk of developing IA. The association of …