Figure see more 2 UniFrac PCoA of dust sample nucITS library clone frequencies. The first and second principal coordinates (P1 and P2) are shown. The first axis correlates with building (P1, red circles, 23% of variation). Apart from reference sample Re1a, the second axis correlates with building conditions (P2, blue circles, 16% of variation). The circles were drawn manually. The UniFrac program was subsequently used to conduct a tree-based analysis to determine which fungal clusters occurred

in individual samples at a significantly higher frequency than expected (compared to random OTU distribution). The results of this analysis are presented in Figure 3; the detailed OTU composition of the clusters shown in the figure is given in Additional file 2 Table S1. Ten phylogenetic clusters (clusters # 1, 5, 12,17-19, 29, 46, 49 and 53) occurred in one or both index buildings at a higher than expected frequency. The Index-2 building was heavily dominated by P. chrysogenum- and P. commune-related OTUs GW-572016 in vivo (cluster 12). In contrast, several clusters (# 1, 5, 17-19) of diverse ascomycete OTUs were characteristic of the Index-1 building. These clusters were affiliated with the classes Dothideomycetes and Eurotiomycetes, and included known colonizers of indoor materials (e.g. Aureobasidium pullulans, Cladophialophora minutissima,

Exophiala xenobiotica, Epicoccum nigrum, Leptosphaerulina chartarum) as well as a variety

of related, unknown OTUs. PF-3084014 research buy Similarly, the basidiomycete clusters characteristic of index buildings (# 29, 46, 49) included potentially building-associated species, e.g. Serpula Sirolimus molecular weight lacrymans, Gloeophyllum sepiarium and Trametes versicolor, yet these phylotypes occurred at a low frequency. Other lineages were associated with the reference buildings. These contained Cladosporium- and Aureobasidium-related Dothideomycetes (# 18, 20) as well as Sordariomycetes (# 23, mainly Fusarium oxysporum) and various yeasts including Cryptococcus spp., Mrakia spp. and Rhodotorula spp. S. cerevisiae, (# 27, 38, 52 and 25, correspondingly). The within-class phylotype richness ratio was elevated (Sn(In)/Sn(Re) = 1.7-13.8) among classes Agaricomycetes, Dothideomycetes and Tremellomycetes in both index buildings in relation to their references (Figure 4). Figure 3 Phylogenetic representation of indoor dust fungal communities inferred from nucITS clone library data. Percentage frequency representation of clusters in individual dust samples are given as a heat map table, also showing cluster numbers (#), class and main genera included. A statistically significantly increased occurrence of a cluster in a sample is shown underlined (UniFrac analysis).