Purpose: The genus Aspergillus and the relative teleomorphs is composed of a large number of species, some of which are of relevance to human health, being responsible for respiratory infection (aspergillosis), for mycotoxicosis and for allergies. Taxa belonging to the genus Aspergillus were frequently isolated from bioaerosol in different workplaces but, despite a great number of these filamentous fungi can highly differ in their mycotoxin profiles, allergic reactions, etc., rarely have been adequately identified, e.g. at the species or at a higher taxonomic resolution. The accurate detection of the microfungi can be basilar for evaluating the exposure to specific airborne conidia or to other fungal products and the occupational risks (even if not easily quantifiable), thus for adopting the appropriate preventive health measures. Recently, the molecular approach has been used in order to avoid the poor characterization of Aspergillus isolates that would result from using only methods based on culture isolation and observations of morphological traits. Indeed molecular phylogenetic studies have shown that morphological characteristics may not be reliable for distinguishing closely related Aspergillus species. Methods: In our ongoing study, we are using a multilocus sequence approach to investigate Aspergillus isolates recovered from various environmental origins and from (generally outdoor) workplaces. Results: Besides the macro- and micromorphological analysis, the Aspergillus isolates were subjected to phylogenetic investigation based on DNA sequencing analysis to gather information on their evolutionary relationships. As molecular markers, of the ribosomal genes we used the internal transcribed spacers, the 5.8S rDNA gene and the domain D1 and D2 of the 28S rDNA gene. In addition, two protein-coding regions, the tubulin beta chain gene (benA) and the calmodulin gene (cmd), were examined because previously proved to be useful for the detection of different microfungi at low taxonomic levels. Conclusions: On the basis of the nucleotide sequence divergence levels of the benA and cmd genes, some Aspergillus strains resulted phylogenetically isolated with high bootstrap values.
Full conference title:
4th Advances Against Aspergillosis
- AAA 4th (2010)