Pathogenic potential of an environmental Aspergillus fumigatus strain recovered from soil of Pygoscelis papua (Gentoo penguins) colony in Antarctica.

Aspergillus fumigatus is a common opportunistic pathogen in different animals, including birds such as penguins. For the first time, a fungal strain identified as A. fumigatus was isolated from soil in the nests of gentoo penguins, Pygoscelis papua, on Livingston Island, South Shetland Islands (maritime Antarctica). This isolate (A. fumigatus UFMGCB 11829) displayed a series of potentially pathogenic characteristics in vitro. We evaluated its detailed molecular taxonomy and submitted the A. fumigatus UFMGCB 11829 Antarctic strain to in vivo pathogenic modelling. The isolate was confirmed to represent A. fumigatus morphological and phylogenetic analysis showed that it was closely related to A. fumigatus sequences reported from animals, immunosuppressed humans, storage grains, plants and soils. The strain displayed the best mycelial growth and conidia production at 37 ºC; however, it was also able to grow and produce conidia at 15º, demonstrating its capability to survive and colonize penguin nest at least in the summer season in maritime Antarctica. In pathogenicity tests, healthy mice did not showed symptoms of infection; however, 50% lethality was observed in immunosuppressed mice that were inoculated with 106 and 107 spores. Lethality increased to 100% when inoculated with 108 spores. Our data highlight the potential pathogenicity of opportunistic A. fumigatus that may be present in the Antarctic, and the risks of both their further transfer within Antarctica and outwards to other continents, risks which may be exacerbated due global climatic changes.

Fungi in glacial ice of Antarctica: diversity, distribution and bioprospecting of bioactive compounds.

We identified cultivable fungi present in the glacial ice fragments collected in nine sites across Antarctica Peninsula and assessed their abilities to produce bioactive compounds. Three ice fragments with approximately 20 kg were collected, melted and 3 L filtered through of 0.45 µm sterilized membranes, which were placed on the media Sabouraud agar and minimal medium incubated at 10 °C. We collected 66 isolates classified into 27 taxa of 14 genera. Penicillium palitans, Penicillium sp. 1, Thelebolus balaustiformis, Glaciozyma antarctica, Penicillium sp. 7, Rhodotorula mucilaginosa, and Rhodotorula dairenensis had the highest frequencies. The diversity and richness of the fungal community were high with moderate dominance. Penicillium species were present in all samples, with Penicillium chrysogenum showing the broadest distribution. P. chrysogenum, P. palitans, and Penicillium spp. had trypanocidal, leishmanicidal, and herbicidal activities, with P. chrysogenum having the broadest and highest capability. 1H NMR signals revealed the presence of highly functionalized secondary metabolites in the bioactive extracts. Despite extreme environmental conditions, glacial ice harbours a diverse fungal community, including species never before recorded in the Arctic and Antarctica. Among them, Penicillium taxa may represent wild fungal strains with genetic and biochemical pathways that may produce new secondary bioactive metabolites.

Indirect Manganese Removal by Stenotrophomonas sp. and Lysinibacillus sp. Isolated from Brazilian Mine Water.

Manganese is a contaminant in the wastewaters produced by Brazilian mining operations, and the removal of the metal is notoriously difficult because of the high stability of the Mn(II) ion in aqueous solutions. To explore a biological approach for removing excessive amounts of aqueous Mn(II), we investigated the potential of Mn(II) oxidation by both consortium and bacterial isolates from a Brazilian manganese mine. A bacterial consortium was able to remove 99.7% of the Mn(II). A phylogenetic analysis of isolates demonstrated that the predominant microorganisms were members of Stenotrophomonas, Bacillus, and Lysinibacillus genera. Mn(II) removal rates between 58.5% and 70.9% were observed for Bacillus sp. and Stenotrophomonas sp. while the Lysinibacillus isolate 13P removes 82.7%. The catalytic oxidation of Mn(II) mediated by multicopper oxidase was not properly detected; however, in all of the experiments, a significant increase in the pH of the culture medium was detected. No aggregates inside the cells grown for a week were found by electronic microscopy. Nevertheless, an energy-dispersive X-ray spectroscopy of the isolates revealed the presence of manganese in Stenotrophomonas sp. and Lysinibacillus sp. grown in K medium. These results suggest that members of Stenotrophomonas and Lysinibacillus genera were able to remove Mn(II) by a nonenzymatic pathway.