Diversity and bioactivity of cultured aquatic fungi from the High Arctic region

This study assessed the diversity and α-glycosidase inhibitory activity of cultured fungi isolated from four aquatic environments （stream, pond, glacial ice, and estuary） in the Ny-A.lesund region （Svalbard, Norway, High Arctic）. A total of 134 fungal isolates were obtained from 13 water samples. Based on morphological characteristics and sequence analyses of the nuclear ribosomal DNA internal transcribed spacer region, these fungal isolates were identified as belonging to 47 species, with 26 belonging to the Ascomycota, 20 to the Basidiomycota, and one to the Zygomycota. The most frequently detected fungal species were Vishniacozyma sp. 2, Cadophora sp. 2, Phenoliferia sp. 1, Dioszegia sp. 2, and Mortierella sp.; these species occurred in 10, eight, seven, six, and five of the samples, respectively. Among the 134 fungal isolates, 17 isolates of 15 species displayed high α-glycosidase inhibitory activity in culture. The results suggest that diverse and distinct populations of cultured fungi are present in Arctic aquatic environments, and they include taxa that are potential sources of bioactive molecules that may be used as prototype drugs for medicinal proposals.

Diversity and interactions of lichen mycobionts and photobionts in the Fildes Region, King George Island, maritime Antarctica

Lichens,as dual organisms comprising a major mycobiont and a major photobiont,exhibit remarkable survival capabilities in extreme conditions,such as those found in Antarctica.Despite their adaptability,the diversity and distribution of lichen photobionts in the ice-free areas of maritime Antarctica remain less understood compared to their mycobiont counterparts.In our study,we investigated the diversity of both lichen mycobionts and photobionts in 56 samples collected from the Fildes Region on King George Island,maritime Antarctica.Through sequencing of the nuclear ribosomal internal transcribed spacer regions and subsequent phylogenetic analysis,we examined the relationships and association patterns between mycobionts and photobionts.Our findings revealed 19 taxa of lichen mycobionts across 13 families and seven orders,along with nine photobiont species within the class Trebouxiophyceae.These photobionts encompassed six Trebouxia species,one Asterochloris species,one Chloroidium species,and one Stichococcus species.In particular,a new Trebouxia lineage(Trebouxia sp.OTU D08)and a new Chloroidium lineage were found.The analysis indicated that many mycobionts could be associated with multiple photobiont species,a pattern also observed among the photobionts.These results contribute significantly to our understanding of the complex diversity of lichen mycobionts and photobionts in the ice-free areas of maritime Antarctica.