4 research outputs found
An interactive tool for the identification of airborne and food fungi
The growth of fungi may result in several kinds of food-spoilage:
off-flavours, discolouration, rotting and formation of pathogenic or allergenic
propagules. Moreover many foodborne fungi produce mycotoxins and thus
fungal growth in foods and feeds should be avoided. Much interest has also
grown for the fungi present in indoor environments, since exposure to airborne
biological agents in both the occupational and residential environments could
be associated with a wide range of adverse health effects with major public
health impact, including infectious diseases, acute toxic effects, allergies and
cancer. An interactive identification tool was created for food- and airborne
microfungi at the genus and/or species level, based on morphological and
physiological data, using the software FRIDA. The interactive key can also
be stored on CD- or DVD-roms, or used on media such as PocketPCs of
Smartphones. Our key allows the identification of 59 genera/groups and 217
species belonging mainly to Zygomycota and anamorphic and teleomorphic
Ascomycota. The database comes with a set of detailed descriptions of each
genus and species, a rich archive of images, a glossary of the most frequent
mycological terms, and references to descriptions; in addition, culture
condition requirements for identification are provided
Development and Use of Flow Cytometry for Detection of Airborne Fungi
Traditional methods for the enumeration of airborne fungi are slow, tedious, and rather imprecise. In this study, the possibility of using flow cytometry (FCM) for the assessment of exposure to the fungus aerosol was evaluated. Epifluorescence microscopy direct counting was adopted as the standard for comparison. Setting up of the method was achieved with pure suspensions of Aspergillus fumigatus and Penicillium brevicompactum conidia at different concentrations, and then analyses were extended to field samples collected by an impinger device. Detection and quantification of airborne fungi by FCM was obtained combining light scatter and propidium iodide red fluorescence parameters. Since inorganic debris are unstainable with propidium iodide, the biotic component could be recognized, whereas the preanalysis of pure conidia suspensions of some species allowed us to select the area corresponding to the expected fungal population. A close agreement between FCM and epifluorescence microscopy counts was found. Moreover, data processing showed that FCM can be considered more precise and reliable at any of the tested concentrations
Vitality and genetic fidelity of white-rot fungi mycelia following different methods of preservation
Basidiomycetes present specific problems with regard to their preservation, because most of them do not form resistant propagules in culture but exist only as mycelium. Usually these fungi can only be preserved by serial transfer on agar (labour-intensive procedures that can increase the danger of variation or loss of physiological or morphological features), or cryopreserved in liquid nitrogen (expensive). Cryopreservation at -80 degrees C and lyophilisation could be good alternatives.
In this work we set up and tested six protocols of cryopreservation at -80 degrees C, and 12 protocols of lyophilisation on 15 isolates of white-rot fungi (WRF) belonging to 10 species. The tested protocols were mainly characterized by the use of different growth media, protectants, time and number of perfusion with protectants and finally by the typology and origin of the samples to be cryopreserved (mycelium/agar plug, whole colony) or to lyophilise (mycelium/agar plug, mycelium fragment, whole colony). Cryopreservation and lyophilisation outcomes were checked, at morphological (macro- and microscopic features), physiological (growth rate and laccase, Mn-independent and Mn-dependent peroxidases activities) and genetic level (Amplified Fragment Length Polymorphisms analysis - AFLP). Vitality of all fungi was successfully preserved by all cryopreservation protocols at -80 degrees C, and by two lyophilisation methods. Our results showed that cryopreservation at -80 degrees C did not produce morphological changes in any isolate, while two isolates were affected by lyophilisation. None of the physiological features were lost, even though growth rate and enzyme activities were somehow influenced by all preservation methods. AFLP analysis showed that only the two isolates that varied in their morphology after lyophilisation produced a different DNA fingerprint pattern in comparison with that obtained before lyophilisation. These findings provide evidence that cryopreservation at -80 degrees C and lyophilisation are suitable alternatives to liquid nitrogen cryopreservation for preservation of some WRF strains. (C) 2009 The British Mycological Society. Published by Elsevier Ltd. All rights reserved