Fungal diversity present in snow sampled in summer in the north-west Antarctic Peninsula and the South Shetland Islands, Maritime Antarctica, assessed using metabarcoding.

We assessed the fungal diversity present in snow sampled during summer in the north-west Antarctic Peninsula and the South Shetland Islands, maritime Antarctica using a metabarcoding approach. A total of 586,693 fungal DNA reads were obtained and assigned to 203 amplicon sequence variants (ASVs). The dominant phylum was Ascomycota, followed by Basidiomycota, Mortierellomycota, Chytridiomycota and Mucoromycota. Penicillium sp., Pseudogymnoascus pannorum, Coniochaeta sp., Aspergillus sp., Antarctomyces sp., Phenoliferia sp., Cryolevonia sp., Camptobasidiaceae sp., Rhodotorula mucilaginosa and Bannozyma yamatoana were assessed as abundant taxa. The snow fungal diversity indices were high but varied across the different locations sampled. Of the fungal ASVs detected, only 28 were present all sampling locations. The 116 fungal genera detected in the snow were dominated by saprotrophic taxa, followed by symbiotrophic and pathotrophic. Our data indicate that, despite the low temperature and oligotrophic conditions, snow can host a richer mycobiome than previously reported through traditional culturing studies. The snow mycobiome includes a complex diversity dominated by cosmopolitan, cold-adapted, psychrophilic and endemic taxa. While saprophytes dominate this community, a range of other functional groups are present.

Fungal and fungal-like diversity present in ornithogenically influenced maritime Antarctic soils assessed using metabarcoding.

We assessed soil fungal and fungal-like diversity using metabarcoding in ornithogenically influenced soils around nests of the bird species Phalacrocorax atriceps, Macronectes giganteus, Pygoscelis antarcticus, and Pygoscelis adelie on the South Shetland Islands, maritime Antarctic. A total of 1,392,784 fungal DNA reads was obtained and assigned to 186 amplicon sequence variants (ASVs). The dominant fungal phylum was Ascomycota, followed by Basidiomycota, Chytridiomycota, Blastocladiomycota, Rozellomycota, Mortierellomycota, Monoblepharomycota, Aphelidiomycota, Basidiobolomycota, Mucoromycota, and the fungal-like Oomycota (Stramenopila), in rank order. Antarctomyces sp., Blastocladiomycota sp., Pseudogymnoascus pannorum, Microascaceae sp., Mortierella sp., Lobulomycetales sp., Sordariomycetes sp., Fungal sp., Rhizophydiales sp., Pseudeurotiaceae sp., Chytridiomycota sp. 1, Filobasidiella sp., Tausonia pullulans, Betamyces sp., and Leucosporidium sp. were the most abundant assigned taxa. The fungal assemblages present in the different ornithogenically influenced soils displayed different diversity indices. However, in general, we detected high fungal diversity and few taxa shared between the samples. Despite the polyextreme environmental conditions experienced in these Antarctic soils, the metabarcoding approach detected a rich and complex fungal community dominated by saprophytes, but with some pathogenic taxa also present. The community was dominated by psychrophilic and psychrotolerant taxa, some apparently endemic to Antarctica, and those identified only at higher taxonomic levels, which may represent currently undescribed fungi. The mycobiome detected included taxa characterized by different ecological roles, including saprotrophic, human- and animal-associated, phytopathogenic, mutualistic, and cosmopolitan. These fungi may potentially be dispersed by birds or in the air column over great distances, including between different regions within Antarctica and from South America, Africa, and Oceania.

Investigating non-fungal eukaryotic diversity in snow in the Antarctic Peninsula region using DNA metabarcoding.

Snow is a unique microhabitat, despite being a harsh environment, multiple life forms have adapted to survive in it. While algae, bacteria and fungi are dominant microorganisms in Antarctic snow, little is known about other organisms that may be present in this habitat. We used metabarcoding to investigate DNA sequence diversity of non-fungal eukaryotes present in snow obtained from six different sites across the Maritime Antarctica. A total of 20 taxa were assigned to obtained sequences, representing five Kingdoms (Chromista, Protozoa, Viridiplantae and Metazoa) and four phyla (Ciliophora, Cercozoa, Chlorophyta and Cnidaria). The highest diversity indices were detected in Trinity Peninsula followed by Robert Island, Arctowski Peninsula, Deception Island, King George Island and Snow Island. The most abundant assignments were to Trebouxiophyceae, followed by Chlamydomonas nivalis and Chlamidomonadales. No taxa were detected at all sites. Three potentially new records for Antarctica were detected: two Ciliophora (Aspidisca magna and Stokesia sp.) and the green algae Trebouxia potteri. Our data suggested that similarities found between the sites may be more related with snow physicochemical properties rather than geographic proximity or latitude. This study provides new insights into the diversity and distribution of eukaryotic organisms in Antarctic snow.

Spathaspora brunopereirae sp. nov. and Spathaspora domphillipsii sp. nov., two d-xylose-fermenting ascosporogenous yeasts from Amazonian Forest biomes.

Four isolates of Spathaspora species were recovered from rotting wood collected in two Brazilian Amazonian biomes. The isolates produced unconjugated allantoid asci with a single elongated ascospore with curved ends. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the isolates represent two different novel Spathaspora species, phylogenetically related to Sp. boniae. Two isolates were obtained from rotting wood collected in two different sites of the Amazonian forest in the state of Pará. The name Spathaspora brunopereirae sp. nov. is proposed to accommodate these isolates. The holotype of Spathaspora brunopereirae sp. nov. is CBS 16119T (MycoBank MB846672). The other two isolates were obtained from a region of transition between the Amazonian forest and the Cerrado ecosystem in the state of Tocantins. The name Spathaspora domphillipsii sp. nov. is proposed for this novel species. The holotype of Spathaspora domphillipsii sp. nov. is CBS 14229T (MycoBank MB846697). Both species are able to convert d-xylose into ethanol and xylitol, a trait with biotechnological applications.

Soil Fungal Diversity and Ecology Assessed Using DNA Metabarcoding along a Deglaciated Chronosequence at Clearwater Mesa, James Ross Island, Antarctic Peninsula.

We studied the fungal diversity present in soils sampled along a deglaciated chronosequence from para- to periglacial conditions on James Ross Island, north-east Antarctic Peninsula, using DNA metabarcoding. A total of 88 amplicon sequence variants (ASVs) were detected, dominated by the phyla Ascomycota, Basidiomycota and Mortierellomycota. The uncommon phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Zoopagomycota and Basidiobolomycota were detected. Unknown fungi identified at higher hierarchical taxonomic levels (Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. and Rozellomycotina sp.) and taxa identified at generic and specific levels (Mortierella sp., Pseudogymnoascus sp., Mortierella alpina, M. turficola, Neoascochyta paspali, Penicillium sp. and Betamyces sp.) dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Only 12 of the fungal ASVs were detected in all chronosequence soils sampled. Sequences representing saprophytic, pathogenic and symbiotic fungi were detected. Based on the sequence diversity obtained, Clearwater Mesa soils contain a complex fungal community, including the presence of fungal groups generally considered rare in Antarctica, with dominant taxa recognized as cold-adapted cosmopolitan, endemic, saprotrophic and phytopathogenic fungi. Clearwater Mesa ecosystems are impacted by the effects of regional climatic changes, and may provide a natural observatory to understand climate change effects over time.

Unravelling the genetic potential for hydrocarbon degradation in the sediment microbiome of Antarctic islands.

Hydrocarbons may have a natural or anthropogenic origin and serve as a source of carbon and energy for microorganisms in Antarctic soils. Herein, 16S rRNA gene and shotgun sequencing were employed to characterize taxonomic diversity and genetic potential for hydrocarbon degradation of the microbiome from sediments of sites located in two Antarctic islands subjected to different temperatures, geochemical compositions, and levels of presumed anthropogenic impact, named: Crater Lake/Deception Island (pristine area), Whalers Bay and Fumarole Bay/Deception Island (anthropogenic-impacted area), and Hannah Point/Livingston Island (anthropogenic-impacted area). Hydrocarbon concentrations were measured for further correlation analyses with biological data. The majority of the hydrocarbon-degrading genes were affiliated to the most abundant bacterial groups of the microbiome: Proteobacteria and Actinobacteria. KEGG annotation revealed 125 catabolic genes related to aromatic hydrocarbon (styrene, toluene, ethylbenzene, xylene, naphthalene, and polycyclic hydrocarbons) and aliphatic (alkanes and cycloalkanes) pathways. Only aliphatic hydrocarbons, in low concentrations, were detected in all areas, thus not characterizing the areas under study as anthropogenically impacted or nonimpacted. The high richness and abundance of hydrocarbon-degrading genes suggest that the genetic potential of the microbiome from Antarctic sediments for hydrocarbon degradation is driven by natural hydrocarbon occurrence.

Fungal impact on archaeological materials collected at Byers Peninsula Livingston Island, South Shetland Islands, Antarctica.

We identified cultivable fungi present on the surface of five archaeological sealers' artifacts from the beginning of the 19th century collected on Livingston Island, Antarctica. Twenty fungal isolates were recovered and identified using biology molecular methods as taxa of Antarctomyces, Linnemannia, Penicillium, Mortierella, Talaromyces, and Trichoderma. Penicillium was dominant on artifacts stored at 10 and 25 °C. In contrast, Antarctomyces, Linnemania, Mortierella, and Trichoderma occurred only on artifacts stored between 8 °C and 10 °C. Our results showed that the Antarctic artifacts harboured cosmopolitan mesophilic, cold-tolerant, and endemic psychrophilic fungal taxa. The mesophilic fungi might have contaminated the artifacts in situ, during sampling, transport, and/or storage in the laboratory collection or represent dormant but viable form capable to grow on the objects. However, the detection of cold-tolerant and endemic fungi shows that these fungi, when stored between 8 ° and 10 °C, continue growing on the objects, which may supply them with organic nutrients; this may accelerate degradation of artifacts in the collection. Preventive steps should be adopted to avoid further microbial contamination. Sterilised microbiological conditions can be followed during fieldwork and transportation to Brazil. The preventive protocol may represent a better alternative to avoid artifact microbial proliferation to preserve rare Antarctic archaeological heritage.

Using metabarcoding to assess Viridiplantae sequence diversity present in Antarctic glacial ice.

Antarctica contains most of the glacial ice on the planet, a habitat that is largely unexplored by biologists. Recent warming in parts of Antarctica, particularly the Antarctic Peninsula region, is leading to widespread glacial retreat, releasing melt water and, potentially, contained biological material and propagules. In this study, we used a DNA metabarcoding approach to characterize Viridiplantae DNA present in Antarctic glacial ice. Ice samples from six glaciers in the South Shetland Islands and Antarctic Peninsula were analysed, detecting the presence of DNA representing a total of 16 taxa including 11 Chlorophyta (green algae) and five Magnoliophyta (flowering plants). The green algae may indicate the presence of a viable algal community in the ice or simply of preserved DNA, and the sequence diversity assigned included representatives of Chlorophyta not previously recorded in Antarctica. The presence of flowering plant DNA is most likely to be associated with pollen or tissue fragments introduced by humans.

Antarctic Strain of Rhodotorula mucilaginosa UFMGCB 18,377 Attenuates Mucositis Induced by 5-Fluorouracil in Mice.

Mucositis is one of the most strenuous side effects caused by chemotherapy drugs, such as 5-fluorouracil (5-FU), during the treatment of several types of cancers. The disease is so prevalent and aggressive that many patients cannot resist such symptoms. However, despite its frequency and clinical significance, there is no effective treatment to prevent or treat mucositis. Thus, the use of probiotics as an adjuvant for the treatment has gained prominence. In the present study, we evaluated the effectiveness of oral administration of the Antarctic strain of Rhodotorula mucilaginosa UFMGCB 18,377 as an alternative to minimize side effects of 5-FU-induced mucositis in mice. Body weight, food consumption, stool consistency, and presence of blood in the feces were assessed daily in mice orally treated or not with the yeast and submitted or not to experimental mucositis. Blood, bones, and intestinal tissues and fluid were used to determine intestinal permeability and immunological, microbiological, and histopathological parameters. Treatment with R. mucilaginosa UFMGCB 18,377 was able to decrease clinical signs of the disease, such as reduction of food intake and body weight loss, and also decreased the number of intestinal enterobacteria and intestinal length shortening. Additionally, treatment was able to decrease the levels of MPO and EPO activities and inflammatory infiltrates, as well as the histopathological lesions characteristic of mucositis in the jejunum and ileum. Results of the present study showed that the oral administration of R. mucilaginosa UFMGCB 18,377 protected mice against mucositis induced by 5-FU.

The largest moss carpet transplant in Antarctica and its bryosphere cryptic biodiversity.

As part of the reconstruction of the Brazilian Antarctic Station on King George Island, three areas of moss carpet were transplanted to minimize the impact of the new facilities on the local biodiversity. A total of 650 m2 of moss carpet was transplanted to neighboring but previously uncolonized locations and has subsequently survived for the last 3 years. Antarctic moss carpets typically comprise low moss species diversity and are often monospecific. We investigated the cryptic biodiversity that was transplanted along with the carpets using a metabarcoding approach through high throughput sequencing. We targeted 16S rRNA for Bacteria and Archaea, ITS for Fungi and Viridiplantae and Cox1 for Metazoa. We detected DNA representing 263 taxa from five Kingdoms (Chromista, Fungi, Metazoa, Protista and Viridiplantae), two Domains (Archaea and Bacteria) and 33 Phyla associated with the carpet. This diversity included one Archaea, 189 Bacteria, 24 Chromista, 19 Fungi, eight Metazoa, seven Protista and 16 Viridiplantae. Bacteria was the most abundant, rich and diverse group, with Chromista second in diversity and richness. Metazoa was less diverse but second highest in dominance. This is the first study to attempt transplanting a significant area of moss carpet to minimize anthropogenic environmental damage in Antarctica and to use metabarcoding as a proxy to assess diversity associated with Antarctic moss carpets, further highlighting the importance of such habitats for other organisms and their importance for conservation.

In Vitro and In Vivo Evaluation of the Probiotic Potential of Antarctic Yeasts.

Antarctica is one of the most pristine and inhospitable regions of the planet, mostly inhabited by microorganisms that survive due to unusual metabolic pathways to adapt to its extreme conditions, which could be interesting for the selection of new probiotics. The aim of the present study was to screen in vitro and in vivo putative probiotics among 254 yeasts isolated from different habitats of Antarctica. In vitro selection evaluated functional (growth at 37 °C, resistance to simulated gastric environment, and to bile salts), safety (degradation of mucin, production of ß-haemolysis and resistance to antifungal drugs), and beneficial (production of antagonistic substances and adhesion to pathogens) properties. Twelve yeasts were able to grow at 37 °C, one of which was eliminated to present ß-haemolytic ability. The remained yeasts resisted to gastric simulation and bile salts, but none presented antagonism against the pathogens tested. Because of the high co-aggregation with Salmonella enterica Typhimurium and growth yield, Rhodotorula mucilaginosa UFMGCB 18377 and Saccharomyces cerevisiae UFMGCB 11120 were selected for in vivo steps using mice challenged with S. Typhimurium. Both yeasts reached high faecal population levels when daily administered, but only R. mucilaginosa UFMGCB 18377 protected mice against Salmonella infection presenting a higher survival and reduced weight loss, bacterial translocation to the liver, sIgA intestinal levels, and intestinal and hepatic MPO and EPO activities. Our in vitro and in vivo results suggest that R. mucilaginosa UFMGCB 18377 presents probiotic potential and deserve further studies as candidate of probiotic by-products. In addition, this is the first screening study of yeasts isolated from Antarctic environments and of Rhodotorula genus for probiotic use.

Assessment of fungal diversity present in lakes of Maritime Antarctica using DNA metabarcoding: a temporal microcosm experiment.

We evaluated the fungal diversity in two lakes on the South Shetland Islands, using DNA metabarcoding through high-throughput sequencing (HTS). A microcosm experiment was deployed for two consecutive years in lakes on Deception and King George islands to capture potential decomposer freshwater fungi. Analyses of the baits revealed 258,326 DNA reads distributed in 34 fungal taxa of the phyla Ascomycota, Basidiomycota, Mortierellomycota, Chytridiomycota and Rozellomycota. Tetracladium marchalianum, Tetracladium sp., Rozellomycota sp., Fungal sp. 1 and Fungal sp. 2 were the most common taxa detected. However, the majority of the communities comprised intermediate and rare taxa. Both fungal communities displayed moderate indices of diversity, richness and dominance. Only six taxa were detected in both lakes, including the most dominant T. marchalianum and Tetracladium sp. The high numbers of reads of the known aquatic saprotrophic hyphomycetes T. marchalianum and Tetracladium sp. in the baits suggest that these fungi may digest organic material in Antarctic lakes, releasing available carbon and nutrients to the other aquatic organisms present in the complex lake food web. Our data confirm that the use of cotton baits together with HTS approaches can be appropriate to study the diversity of resident freshwater fungi present in Antarctic lakes.

Antimalarials and Phytotoxins from Botryosphaeria dothidea Identified from a Seed of Diseased Torreya taxifolia.

The metabolic pathways in the apicoplast organelle of Plasmodium parasites are similar to those in plastids in plant cells and are suitable targets for malaria drug discovery. Some phytotoxins released by plant pathogenic fungi have been known to target metabolic pathways of the plastid; thus, they may also serve as potential antimalarial drug leads. An EtOAc extract of the broth of the endophyte Botryosphaeria dothidea isolated from a seed collected from a Torreya taxifolia plant with disease symptoms, showed in vitro antimalarial and phytotoxic activities. Bioactivity-guided fractionation of the extract afforded a mixture of two known isomeric phytotoxins, FRT-A and flavipucine (or their enantiomers, sapinopyridione and (-)-flavipucine), and two new unstable γ-lactam alkaloids dothilactaenes A and B. The isomeric mixture of phytotoxins displayed strong phytotoxicity against both a dicot and a monocot and moderate cytotoxicity against a panel of cell lines. Dothilactaene A showed no activity. Dothilactaene B was isolated from the active fraction, which showed moderate in vitro antiplasmodial activity with high selectivity index. In spite of this activity, its instability and various other biological activities shown by related compounds would preclude it from being a viable antimalarial lead.

Diversity, ecology, and bioprospecting of culturable fungi in lakes impacted by anthropogenic activities in Maritime Antarctica.

In this study, we accessed culturable fungal assemblages present in the sediments of three lakes potentially impacted anthropogenically in the Fildes Peninsula, King George Island, Antarctica and identified 63 taxa. Cladosporium sp. 2, Pseudeurotium hygrophilum, and Pseudogymnoascus verrucosus were recovered from the sampled sediments of all lakes. High concentrations of metals and the lowest fungal diversity indices were detected in the sediments of the Central Lake, which can be influenced by human activities due to their proximity to research stations to those of the other two lakes, which were far from the Antarctic stations. At least one type of biological activity was demonstrated by 40 fungal extracts. Among these, P. hygrophilum, P. verrucosus, Penicillium glabrum, and Penicillium solitum demonstrated strong trypanocidal, herbicidal, and antifungal activities. Our results suggest that an increase of the anthropogenic activities in the region might have affected the microbial diversity and composition. In addition, the fungal diversity in these lakes may be a useful model to study the effect of anthropogenic activities in Antarctica. We isolated a diverse group of fungal taxa from Antarctic lake sediments, which have the potential to produce novel compounds for the both the medical and agriculture sectors.

Diversity and bioprospecting of cultivable fungal assemblages in sediments of lakes in the Antarctic Peninsula.

We recovered 195 fungal isolates from the sediments of different lakes in the Antarctic Peninsula, which were screened to detect bioactive compounds. Forty-two taxa belonging to the phyla Ascomycota, Basidiomycota, and Mortierellomycota were identified. Thelebolus globosus, Antarctomyces psychrotrophicus, Pseudogymnoascus verrucosus, Vishniacozyma victoriae, and Phenoliferia sp. were found to be the most prevalent. The fungal assemblages showed high diversity and richness, but low dominance values. However, the diversity indices and fungal distribution ranged according to the different lake sediments. Sixty fungal extracts displayed at least one biological activity against the evaluated targets. Among them, Pseudogymnoascus destructans showed selective trypanocidal activity, Cladosporium sp. 1 and Trichoderma polysporum showed antifungal activity, and Pseudogymnoascus appendiculatus and Helotiales sp. showed high herbicidal activity. We detected a rich and diverse fungal community composed of cold cosmopolitan and psychrophilic endemic taxa recognized as decomposers, symbiotics, pathogens, and potential new species, in the sediments of Antarctic lakes. The dynamics and balance of this fungal community represents an interesting aquatic web model for further ecological and evolutionary studies under extreme conditions and potential climate changes in the regions. In addition, we detected fungal taxa and isolates able to produce bioactive compounds that may represent the source of prototype molecules for applications in medicine and agriculture.

Cultivable fungi present in deep-sea sediments of Antarctica: taxonomy, diversity, and bioprospecting of bioactive compounds.

We accessed the culturable mycobiota present in marine sediments at different depths in Antarctica Ocean. Acremonium fusidioides, Penicillium allii-sativi, Penicillium chrysogenum, Penicillium palitans, Penicillium solitum, and Pseudogymnoascus verrucosus were identified. Penicillium allii-sativi was the dominant species. At least one isolate of each species was capable to present antifungal, trypanocidal, leishmanicidal, antimalarial, nematocidal, or herbicidal activities. Penicillium produced extracts with strong trypanocidal and antimalarial activities, and the extracts of P. solitum and P. chrysogenum demonstrated strong antimalarial activities. Acremonium fusidioides and P. verrucosus displayed strong selective herbicidal properties. The 1H NMR signals for extracts of A. fusidioides, P. chrysogenum, and P. solitum indicated the presence of highly functionalized secondary metabolites, which may be responsible for the biological activities detected. In the deep marine Antarctic sediments, we detected fungal assemblages in which the Penicillium species were found to be dominant and demonstrated capabilities to survive and/or colonise that poly-extreme habitat. Penicillium being a polyextremophile Antarctic species, exhibited strong biological activities and the presence of aromatic compounds in its extracts may indicate that they are wild ancient strains with high genetic and biochemical potentials that enable them to produce bioactive compounds which can be researched in further studies and used in the chemotherapy of neglected tropical diseases as well as in agriculture.

Diversity and ecology of cultivable fungi isolated from the thermal soil gradients in Deception Island, Antarctica.

We surveyed the diversity of cultivable fungi isolated from cold and hot volcanic soils of Deception Island, Antarctica. Seventy-four fungal isolates were identified; these belonged to 17 taxa in the genera Aspergillus, Penicillium, Pseudogymnoascus, Purpureocillium, and Mortierella. The fungal assemblages showed low diversity, richness, and dominance indices. The Aspergillus taxa were dominant in the soils at 0 °C, 50 °C, and 100 °C. Aspergillus lacticoffeatus, Aspergillus cf. ruber, Penicillium citrinun, and Purpureocillium sodanum were present only in soils having a temperature of 100 °C. Aspergillus calidoustus was present in all thermal soils and displayed the highest densities. The majority of fungi displayed mesophilic behavior; however, different isolates of Aspergillus lacticoffeatus and Aspergillus niger were able to grow at 50 °C; these are phylogenetically close to the causative agents of aspergillosis in immunocompromised individuals. Deception Island perhaps represents one of the most visited regions in Antarctica and the tourism there has increased over the last 20 years, especially by elderly tourists, probably with weak immune systems, come in contact with the resident microorganisms, including the thermo-resistant opportunistic Aspergillus species.

Diversity, Distribution, and Ecology of Fungi in the Seasonal Snow of Antarctica.

We characterized the fungal community found in the winter seasonal snow of the Antarctic Peninsula. From the samples of snow, 234 fungal isolates were obtained and could be assigned to 51 taxa of 26 genera. Eleven yeast species displayed the highest densities; among them, Phenoliferia glacialis showed a broad distribution and was detected at all sites that were sampled. Fungi known to be opportunistic in humans were subjected to antifungal minimal inhibition concentration. Debaryomyces hansenii, Rhodotorula mucilaginosa, Penicillium chrysogenum, Penicillium sp. 3, and Penicillium sp. 4 displayed resistance against the antifungals benomyl and fluconazole. Among them, R. mucilaginosa isolates were able to grow at 37 °C. Our results show that the winter seasonal snow of the Antarctic Peninsula contains a diverse fungal community dominated by cosmopolitan ubiquitous fungal species previously found in tropical, temperate, and polar ecosystems. The high densities of these cosmopolitan fungi suggest that they could be present in the air that arrives at the Antarctic Peninsula by air masses from outside Antarctica. Additionally, we detected environmental fungal isolates that were resistant to agricultural and clinical antifungals and able to grow at 37 °C. Further studies will be needed to characterize the virulence potential of these fungi in humans and animals.

Chemical Characterization and Biotechnological Applicability of Pigments Isolated from Antarctic Bacteria.

Considering the global trend in the search for alternative natural compounds with antioxidant and sun protection factor (SPF) boosting properties, bacterial carotenoids represent an opportunity for exploring pigments of natural origin which possess high antioxidant activity, lower toxicity, no residues, and no environmental risk and are readily decomposable. In this work, three pigmented bacteria from the Antarctic continent, named Arthrobacter agilis 50cyt, Zobellia laminarie 465, and Arthrobacter psychrochitiniphilus 366, were able to withstand UV-B and UV-C radiation. The pigments were extracted and tested for UV absorption, antioxidant capacity, photostability, and phototoxicity profile in murine fibroblasts (3T3 NRU PT-OECD TG 432) to evaluate their further potential use as UV filters. Furthermore, the pigments were identified by ultra-high-performance liquid chromatography-photodiode array detector-mass spectrometry (UPLC-PDA-MS/MS). The results showed that all pigments presented a very high antioxidant activity and good stability under exposure to UV light. However, except for a fraction of the A. agilis 50cyt pigment, they were shown to be phototoxic. A total of 18 different carotenoids were identified from 23 that were separated on a C18 column. The C50 carotenes bacterioruberin and decaprenoxanthin (including its variations) were confirmed for A. agilis 50cyt and A. psychrochitiniphilus 366, respectively. All-trans-bacterioruberin was identified as the pigment that did not express phototoxic activity in the 3T3 NRU PT assay (MPE < 0.1). Zeaxanthin, ß-cryptoxanthin, ß-carotene, and phytoene were detected in Z. laminarie 465. In conclusion, carotenoids identified in this work from Antarctic bacteria open perspectives for their further biotechnological application towards a more sustainable and environmentally friendly way of pigment exploitation.

The diversity, distribution, and pathogenic potential of cultivable fungi present in rocks from the South Shetlands archipelago, Maritime Antarctica.

We studied the molecular taxonomy and diversity of cultivable rock fungi from Antarctic islands. From 50 rock samples, 386 fungal isolates were obtained and identified as 33 taxa of 20 genera. The genera Cladophialophora, Cladosporium, Cyphellophora, Eichleriella, Paracladophialophora, and Penicillium displayed the highest densities. Ecological diversity indices showed that the fungal assemblages are diverse and rich with low dominance. The genera Cladophialophora, Cladosporium, and Penicillium showed a broad distribution from rocks of the various islands. One hundred and fifty-nine fungi, grown at 37 °C, were identified as Penicillium chrysogenum, Fusarium sp., and Rhodotorula mucilaginosa. One hundred and three fungi displayed haemolytic activity, 81 produced proteinase, 9 produced phospholipase, and 25 presented dimorphism and a spore diameter ≤ 4 µm. The Antarctic Peninsula region appears to be under the effects of global climate changes, which may expose and accelerate the rock's weathering processes, and expose and release cryptic fungi and other microbes, especially those with innate pathogenic potential, previously arrested in rocks. Consequently, these rocks and their particles may represent a vehicle for the dispersal of microbial propagules, including those able to spread pathogens, along, across, and out of Antarctica.