Publications by authors named "Laura Zucconi"

44 Publications

Dark-pigmented biodeteriogenic fungi in etruscan hypogeal tombs: New data on their culture-dependent diversity, favouring conditions, and resistance to biocidal treatments.

Fungal Biol 2021 Aug 29;125(8):609-620. Epub 2021 Mar 29.

Dipartimento di Scienze, Università 'Roma Tre', Viale G. Marconi 446 - 00146, Rome, Italy.

Subterranean Cultural Heritage sites are frequently subject to biological colonization due to the high levels of humidity, even in conditions of low irradiance and oligotrophy. Here microorganisms form complex communities that may be dangerous through mineral precipitation, through the softening of materials or causing frequent surface discolorations. A reduction of contamination's sources along with the control of microclimatic conditions and biocide treatments (overall performed with benzalkonium chloride) are necessary to reduce microbial growths. Dark discolorations have been recorded in the painted Etruscan tombs of Tarquinia, two of which have been analyzed to collect taxonomical, physiological, and ecological information. Eighteen dark-pigmented fungi were isolated among a wider culturable fraction: nine from blackening areas and nine from door sealings, a possible route of contamination. Isolates belonged to three major groups: Chaetothyriales, Capnodiales (Family Cladosporiaceae), and Acremonium-like fungi. Exophiala angulospora and Cyphellophora olivacea, a novelty for hypogea, were identified, while others need further investigations as possible new taxa. The metabolic skills of the detected species showed their potential dangerousness for the materials. Their tolerance to benzalkonium chloride-based products suggested a certain favouring effect through the decreasing competitiveness of less resistant species. The type of covering of the dromos may influence the risk of outer contamination. Fungal occurrence can be favoured by root penetration.
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http://dx.doi.org/10.1016/j.funbio.2021.03.003DOI Listing
August 2021

Plant DNA Barcode as a Tool for Root Identification in Hypogea: The Case of the Etruscan Tombs of Tarquinia (Central Italy).

Plants (Basel) 2021 Jun 3;10(6). Epub 2021 Jun 3.

Department of Sciences, Roma Tre University, 00146 Rome, Italy.

Roots can produce mechanical and chemical alterations to building structures, especially in the case of underground historical artifacts. In archaeological sites, where vegetation plays the dual role of naturalistic relevance and potential threat, trees and bushes are under supervision. No customized measures can be taken against herbaceous plants lacking fast and reliable root identification methods that are useful to assess their dangerousness. In this study, we aimed to test the efficacy of DNA barcoding in identifying plant rootlets threatening the Etruscan tombs of the Necropolis of Tarquinia. As DNA barcode markers, we selected two sections of the genes and , the nuclear ribosomal internal transcribed spacer (nrITS), and the intergenic spacer . All fourteen root samples were successfully sequenced and identified at species (92.9%) and genus level (7.01%) by GenBank matching and reference dataset implementation. Some eudicotyledons with taproots, such as L., Mill., and L. subsp. , showed a certain recurrence. Further investigations are needed to confirm this promising result, increasing the number of roots and enlarging the reference dataset with attention to meso-Mediterranean perennial herbaceous species. The finding of herbaceous plants roots at more than 3 m deep confirms their potential risk and underlines the importance of vegetation planning, monitoring, and management on archaeological sites.
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http://dx.doi.org/10.3390/plants10061138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8228792PMC
June 2021

Highly differentiated soil bacterial communities in Victoria Land macro-areas (Antarctica).

FEMS Microbiol Ecol 2021 07;97(7)

Department of Ecological and Biological Sciences, University of Tuscia, Largo dell'Università s.n.c., 01100, Viterbo, Italy.

Ice-free areas of Victoria Land, in Antarctica, are characterized by different terrestrial ecosystems, that are dominated by microorganisms supporting highly adapted communities. Despite the unique conditions of these ecosystems, reports on their bacterial diversity are still fragmentary. From this perspective, 60 samples from 14 localities were analyzed. These localities were distributed in coastal sites with differently developed biological soil crusts, inner sites in the McMurdo Dry Valleys with soils lacking of plant coverage, and a site called Icarus Camp, with a crust developed on a thin locally weathered substrate of the underlying parent granitic-rock. Bacterial diversity was studied through 16S rRNA metabarcoding sequencing. Communities diversity, composition and the abundance and composition of different taxonomic groups were correlated to soil physicochemical characteristics. Firmicutes, Bacteroidetes, Cyanobacteria and Proteobacteria dominated these communities. Most phyla were mainly driven by soil granulometry, an often disregarded parameter and other abiotic parameters. Bacterial composition differed greatly among the three macrohabitats, each having a distinct bacterial profile. Communities within the two main habitats (coastal and inner ones) were well differentiated from each other as well, therefore depending on site-specific physicochemical characteristics. A core community of the whole samples was observed, mainly represented by Firmicutes and Bacteroidetes.
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http://dx.doi.org/10.1093/femsec/fiab087DOI Listing
July 2021

Growth Forms and Functional Guilds Distribution of Soil Fungi in Coastal Versus Inland Sites of Victoria Land, Antarctica.

Biology (Basel) 2021 Apr 11;10(4). Epub 2021 Apr 11.

Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.

In Victoria Land, Antarctica, ice-free areas are restricted to coastal regions and dominate the landscape of the McMurdo Dry Valleys. These two environments are subjected to different pressures that determine the establishment of highly adapted fungal communities. Within the kingdom of fungi, filamentous, yeasts and meristematic/microcolonial growth forms on one side and different lifestyles on the other side may be considered adaptive strategies of particular interest in the frame of Antarctic constraints. In this optic, soil fungal communities from both coastal and Dry Valleys sites, already characterized thorough ITS1 metabarcoding sequencing, have been compared to determine the different distribution of phyla, growth forms, and lifestyles. Though we did not find significant differences in the richness between the two environments, the communities were highly differentiated and Dry Valleys sites had a higher evenness compared to coastal ones. Additionally, the distribution of different growth forms and lifestyles were well differentiated, and their diversity and composition were likely influenced by soil abiotic parameters, among which soil granulometry, pH, P, and C contents were the potential main determinants.
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http://dx.doi.org/10.3390/biology10040320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070035PMC
April 2021

Microbial activity in alpine soils under climate change.

Sci Total Environ 2021 Aug 10;783:147012. Epub 2021 Apr 10.

Department of Ecological and Biological Sciences, University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy. Electronic address:

Soil enzymatic activity was assessed in the Stelvio Pass area (Italian Central Alps) aiming to define the possible effects of climate change on microbial functioning. Two sites at two different elevations were chosen, a subalpine (2239 m) and an alpine belt (2604-2624 m), with mean annual air temperature differing by almost 3 °C, coherent with the worst future warming scenario (RCP 8.5) by 2100. The lower altitude site may represent a proxy of the potential future situation at higher altitude after the upward shift of subalpine vegetation due to climate change. Additionally, hexagonal open top chambers (OTCs) were installed at the upper site, to passively increase by about 2 °C the summer inner temperature to simulate short term effects of warming before the vegetation shift takes place. Soil physicochemical properties and the bacterial and fungal abundances of the above samples were also considered. The subalpine soils showed a higher microbial activity, especially for hydrolytic enzymes, higher carbon, ammonium and hydrogen (p < 0.001) contents, and a slightly higher PO content (p < 0.05) than alpine soils. Bacterial abundance was higher than fungal abundance, both for alpine and subalpine soils. On the other hand, the short term effect, which increased the mean soil temperature during the peak of the growing season in the OTC, showed to induce scarcely significant differences for edaphic parameters and microbial biomass content among the warmed and control plots. Using the manipulative warming experiments, we demonstrated that warming is able to change the enzyme activity starting from colder and higher altitude sites, known to be more vulnerable to the rising temperatures associated with climate change. Although five-years of experimental warming does not allow us to make bold conclusions, it appeared that warming-induced upwards vegetation shift might induce more substantial changes in enzymatic activities than the short-term effects, in the present vegetation context.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147012DOI Listing
August 2021

Additions to Italian Pleosporinae, including sp. nov.

Biodivers Data J 2021 18;9:e59648. Epub 2021 Jan 18.

Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand Center of Excellence in Fungal Research, Mae Fah Luang University Chiang Rai 57100 Thailand.

Background: In the last few years, many microfungi-including plant-associated species-have been reported from various habitats and substrates in Italy. In this study of pleosporalean fungi, we researched terrestrial habitats in the Provinces of Arezzo (Tuscany region), Forlì-Cesena and Ravenna (Emilia-Romagna region) in Italy.

New Information: Our research on Italian pleosporalean fungi resulted in the discovery of a new species, (Phaeosphaeriaceae). In addition, we present a new host record for (Phaeosphaeriaceae) and the second Italian record of (Didymellaceae). Species boundaries were defined, based on morphological study and multi-locus phylogenetic reconstructions using Maximum Likelihood and Bayesian Inference analyses. Our findings expand the knowledge on host and distribution ranges of pleosporalean fungi in Italy.
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http://dx.doi.org/10.3897/BDJ.9.e59648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835198PMC
January 2021

Extracellular Enzymes and Bioactive Compounds from Antarctic Terrestrial Fungi for Bioprospecting.

Int J Environ Res Public Health 2020 09 4;17(18). Epub 2020 Sep 4.

Department of Earth and Environmental Sciences, University of Pavia, via S. Epifanio 14, 27100 Pavia, Italy.

Antarctica, one of the harshest environments in the world, has been successfully colonized by extremophilic, psychrophilic, and psychrotolerant microorganisms, facing a range of extreme conditions. Fungi are the most diverse taxon in the Antarctic ecosystems, including soils. Genetic adaptation to this environment results in the synthesis of a range of metabolites, with different functional roles in relation to the biotic and abiotic environmental factors, some of which with new biological properties of potential biotechnological interest. An overview on the production of cold-adapted enzymes and other bioactive secondary metabolites from filamentous fungi and yeasts isolated from Antarctic soils is here provided and considerations on their ecological significance are reported. A great number of researches have been carried out to date, based on cultural approaches. More recently, metagenomics approaches are expected to increase our knowledge on metabolic potential of these organisms, leading to the characterization of unculturable taxa. The search on fungi in Antarctica deserves to be improved, since it may represent a useful strategy for finding new metabolic pathways and, consequently, new bioactive compounds.
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http://dx.doi.org/10.3390/ijerph17186459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7558612PMC
September 2020

sp. nov. and sp. nov., two novel basidiomycetous yeast species isolated from cold environments.

Int J Syst Evol Microbiol 2020 Aug 22;70(8):4704-4713. Epub 2020 Jul 22.

Department of Agricultural, Food and Environmental Sciences & Industrial yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy.

Five yeast strains were isolated from soil and sediments collected from Alps and Apennines glaciers during sampling campaigns carried out in summer 2007 and 2017, respectively. Based on morphological and physiological tests and on phylogenetic analyses reconstructed with ITS and D1/D2 sequences, the five strains were considered to belong to two related but hitherto unknown species within the genus , in an intermediate position between and . The names (holotype DBVPG 10734) and (holotype DBVPG 10736) are proposed for the two novel species and a detailed description of their morphological, physiological and phylogenetic features are presented. Both species fermented glucose, sucrose and trehalose, which is an uncommon feature in basidiomycetous yeasts, and showed septate hyphae with teliospore formation.
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http://dx.doi.org/10.1099/ijsem.0.004336DOI Listing
August 2020

In Vitro Propagation of (Isoetaceae): A Key Conservation Challenge for a Critically Endangered Quillwort.

Plants (Basel) 2020 Jul 14;9(7). Epub 2020 Jul 14.

Tuscia Germplasm Bank, Tuscia University, largo dell'Università-blocco C, 01100 Viterbo, Italy.

is an aquatic quillwort endemic to Italy. It is one of the rarest quillworts in Europe, and is critically endangered due to restricted range and to the continuous decline of both population and habitat quality. This study aims to develop an optimized protocol to reproduce and grow sporelings. Mature and immature megaspores were mixed with mature microspores to evaluate the influence of the developmental stage on germination and sporeling development. Two substrates, distilled water and water-agar medium, were tested for germination and sporeling emergence, and three substrates, sand, lake sediment and water-agar, were tested for transplants. A high percentage of megaspore germination (a total of 79.1%) was obtained in both substrates, higher for mature than immature spores. A total of 351 sporelings were produced in distilled water and water-agar cultures, with similar percentages (64.5% and 69.6%, respectively). The development stage of the megaspores affected both germination and sporeling development. Sporeling emergence showed significantly higher percentages in mature megaspores than immature ones (69.6% vs. 11.6%, respectively), with 85% of germinated spores developing sporelings. Only transplants over water-agar medium were successful. This protocol could be useful for the propagation of sporelings as the key step towards the planning of in situ actions to save this Mediterranean quillwort from extinction.
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http://dx.doi.org/10.3390/plants9070887DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7412419PMC
July 2020

Expansion of shrubs could result in local loss of soil bacterial richness in Western Greenland.

FEMS Microbiol Ecol 2020 08;96(8)

Biodiversity Dynamics Research Group, Naturalis Biodiversity Center, Leiden, The Netherlands.

Climate warming in Greenland is facilitating the expansion of shrubs across wide areas of tundra. Given the close association between plants and soil microorganisms and the important role of soil bacteria in ecosystem functioning, it is of utmost importance to characterize microbial communities of arctic soil habitats and assess the influence of plant edaphic factors on their composition. We used 16S rRNA gene amplicons to explore the bacterial assemblages of three different soil habitats representative of a plant coverage gradient: bare ground, biological soil crusts dominated by mosses and lichens and vascular vegetation dominated by shrubs. We investigated how bacterial richness and community composition were affected by the vegetation coverage, and soil pH, moisture and carbon (C), nitrogen (N) and phosphorus (P) contents. Bacterial richness did not correlate with plant coverage complexity, while community structure varied between habitats. Edaphic variables affected both the taxonomic richness and community composition. The high number of Amplicon Sequence Variants (ASVs) indicators of bare ground plots suggests a risk of local bacterial diversity loss due to expansion of vascular vegetation.
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http://dx.doi.org/10.1093/femsec/fiaa089DOI Listing
August 2020

Uncovered Microbial Diversity in Antarctic Cryptoendolithic Communities Sampling three Representative Locations of the Victoria Land.

Microorganisms 2020 Jun 23;8(6). Epub 2020 Jun 23.

Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.

The endolithic niche represents an ultimate refuge to microorganisms in the Mars-like environment of the Antarctic desert. In an era of rapid global change and desertification, the interest in these border ecosystems is increasing due to speculation on how they maintain balance and functionality at the dry limits of life. To assure a reliable estimation of microbial diversity, proper sampling must be planned in order to avoid the necessity of re-sampling as reaching these remote locations is risky and requires tremendous logistical and economical efforts. In this study, we seek to determine the minimum number of samples for uncovering comprehensive bacterial and fungal diversity, comparing communities in strict vicinity to each other. We selected three different locations of the Victoria Land (Continental Antarctica) at different altitudes and showing sandstone outcrops of a diverse nature and origin-Battleship promontory (834 m above sea level (a.s.l.), Southern VL), Trio Nunatak (1,470 m a.s.l., Northern VL) and Mt New Zealand (3,100 m a.s.l., Northern VL). Overall, we found that a wider sampling would be required to capture the whole amplitude of microbial diversity, particularly in Northern VL. We concluded that the inhomogeneity of the rock matrix and the stronger environmental pressure at higher altitudes may force the communities to a higher local diversification.
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http://dx.doi.org/10.3390/microorganisms8060942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356261PMC
June 2020

Intra- and inter-cores fungal diversity suggests interconnection of different habitats in an Antarctic frozen lake (Boulder Clay, Northern Victoria Land).

Environ Microbiol 2020 08 30;22(8):3463-3477. Epub 2020 Jun 30.

Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy.

A perennially frozen lake at Boulder Clay site (Victoria Land, Antarctica), characterized by the presence of frost mounds, have been selected as an in situ model for ecological studies. Different samples of permafrost, glacier ice and brines have been studied as a unique habitat system. An additional sample of brines (collected in another frozen lake close to the previous one) was also considered. Alpha- and beta-diversity of fungal communities showed both intra- and inter-cores significant (p < 0.05) differences, which suggest the presence of interconnection among the habitats. Therefore, the layers of frost mound and the deep glacier could be interconnected while the brines could probably be considered as an open habitat system not interconnected with each other. Moreover, the absence of similarity between the lake ice and the underlying permafrost suggested that the lake is perennially frozen based. The predominance of positive significant (p < 0.05) co-occurrences among some fungal taxa allowed to postulate the existence of an ecological equilibrium in the habitats systems. The positive significant (p < 0.05) correlation between salt concentration, total organic carbon and pH, and some fungal taxa suggests that a few abiotic parameters could drive fungal diversity inside these ecological niches.
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http://dx.doi.org/10.1111/1462-2920.15117DOI Listing
August 2020

Endolithic Fungal Species Markers for Harshest Conditions in the McMurdo Dry Valleys, Antarctica.

Life (Basel) 2020 Feb 6;10(2). Epub 2020 Feb 6.

Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.

The microbial communities that inhabit lithic niches inside sandstone in the Antarctic McMurdo Dry Valleys of life's limits on Earth. The cryptoendolithic communities survive in these ice-free areas that have the lowest temperatures on Earth coupled with strong thermal fluctuations, extreme aridity, oligotrophy and high levels of solar and UV radiation. In this study, based on DNA metabarcoding, targeting the fungal Internal Transcribed Spacer region 1 (ITS1) and multivariate statistical analyses, we supply the first comprehensive overview onto the fungal diversity and composition of these communities sampled over a broad geographic area of the Antarctic hyper-arid cold desert. Six locations with surfaces that experience variable sun exposure were sampled to compare communities from a common area across a gradient of environmental pressure. The Operational Taxonomic Units (OTUs) identified were primarily members of the Ascomycota phylum, comprised mostly of the Lecanoromycetes and Dothideomycetes classes. The fungal species , endemic to Antarctica, was found to be a marker species to the harshest conditions occurring in the shady, south exposed rock surfaces. Analysis of community composition showed that sun exposure was an environmental property that explained community diversity and structured endolithic colonization.
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http://dx.doi.org/10.3390/life10020013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175349PMC
February 2020

Vegetation, pH and Water Content as Main Factors for Shaping Fungal Richness, Community Composition and Functional Guilds Distribution in Soils of Western Greenland.

Front Microbiol 2019 11;10:2348. Epub 2019 Oct 11.

Biodiversity Dynamics, Naturalis Biodiversity Center, Leiden, Netherlands.

Fungi are the most abundant and one of the most diverse components of arctic soil ecosystems, where they are fundamental drivers of plant nutrient acquisition and recycling. Nevertheless, few studies have focused on the factors driving the diversity and functionality of fungal communities associated with these ecosystems, especially in the scope of global warming that is particularly affecting Greenland and is leading to shrub expansion, with expected profound changes of soil microbial communities. We used soil DNA metabarcoding to compare taxonomic and functional composition of fungal communities in three habitats [bare ground (BG), biological soil crusts (BSC), and vascular vegetation (VV) coverage] in Western Greenland. Fungal richness increased with the increasing complexity of the coverage, but BGs and BSCs samples showed the highest number of unique OTUs. Differences in both fungal community composition and distribution of functional guilds identified were correlated with edaphic factors (mainly pH and water content), in turn connected with the different type of coverage. These results suggest also possible losses of diversity connected to the expansion of VV and possible interactions among the members of different functional guilds, likely due to the nutrient limitation, with potential effects on elements recycling.
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http://dx.doi.org/10.3389/fmicb.2019.02348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797927PMC
October 2019

Altitude and fungal diversity influence the structure of Antarctic cryptoendolithic Bacteria communities.

Environ Microbiol Rep 2019 10 26;11(5):718-726. Epub 2019 Aug 26.

Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy.

Endolithic growth within rocks is a critical adaptation of microbes living in harsh environments where exposure to extreme temperature, radiation, and desiccation limits the predominant life forms, such as in the ice-free regions of Continental Antarctica. The microbial diversity of the endolithic communities in these areas has been sparsely examined. In this work, diversity and composition of bacterial assemblages in the cryptoendolithic lichen-dominated communities of Victoria Land (Continental Antarctica) were explored using a high-throughput metabarcoding approach, targeting the V4 region of 16S rDNA. Rocks were collected in 12 different localities (from 14 different sites), along a gradient ranging from 1000 to 3300 m a.s.l. and at a sea distance ranging from 29 to 96 km. The results indicate Actinobacteria and Proteobacteria are the dominant taxa in all samples and defined a 'core' group of bacterial taxa across all sites. The structure of bacteria communities is correlated with the fungal counterpart and among the environmental parameters considered, altitude was found to influence bacterial biodiversity, while distance from sea had no evident influence.
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http://dx.doi.org/10.1111/1758-2229.12788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8057506PMC
October 2019

Draft Genome Sequence of an Antarctic Isolate of the Black Yeast Fungus .

Microbiol Resour Announc 2019 May 9;8(19). Epub 2019 May 9.

Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, California, USA

A 30.43-Mb draft genome sequence with 10,355 predicted protein-coding genes was produced for the ascomycete fungus strain CCFEE 6314, a black yeast isolated from Antarctic cryptoendolithic communities. The sequence will be of importance for identifying differences among extremophiles and mesophiles and cataloguing the global population diversity of this organism.
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http://dx.doi.org/10.1128/MRA.00142-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6509517PMC
May 2019

Limits of Life and the Habitability of Mars: The ESA Space Experiment BIOMEX on the ISS.

Astrobiology 2019 02;19(2):145-157

20 Extremophile Research & Biobank CCCryo, Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany.

BIOMEX (BIOlogy and Mars EXperiment) is an ESA/Roscosmos space exposure experiment housed within the exposure facility EXPOSE-R2 outside the Zvezda module on the International Space Station (ISS). The design of the multiuser facility supports-among others-the BIOMEX investigations into the stability and level of degradation of space-exposed biosignatures such as pigments, secondary metabolites, and cell surfaces in contact with a terrestrial and Mars analog mineral environment. In parallel, analysis on the viability of the investigated organisms has provided relevant data for evaluation of the habitability of Mars, for the limits of life, and for the likelihood of an interplanetary transfer of life (theory of lithopanspermia). In this project, lichens, archaea, bacteria, cyanobacteria, snow/permafrost algae, meristematic black fungi, and bryophytes from alpine and polar habitats were embedded, grown, and cultured on a mixture of martian and lunar regolith analogs or other terrestrial minerals. The organisms and regolith analogs and terrestrial mineral mixtures were then exposed to space and to simulated Mars-like conditions by way of the EXPOSE-R2 facility. In this special issue, we present the first set of data obtained in reference to our investigation into the habitability of Mars and limits of life. This project was initiated and implemented by the BIOMEX group, an international and interdisciplinary consortium of 30 institutes in 12 countries on 3 continents. Preflight tests for sample selection, results from ground-based simulation experiments, and the space experiments themselves are presented and include a complete overview of the scientific processes required for this space experiment and postflight analysis. The presented BIOMEX concept could be scaled up to future exposure experiments on the Moon and will serve as a pretest in low Earth orbit.
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http://dx.doi.org/10.1089/ast.2018.1897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383581PMC
February 2019

Survival and redox activity of Friedmanniomyces endolithicus, an Antarctic endemic black meristematic fungus, after gamma rays exposure.

Fungal Biol 2018 12 23;122(12):1222-1227. Epub 2018 Oct 23.

College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada.

Despite living organisms are not exposed to acute ionizing radiation under natural conditions, some exhibit a high radiation resistance. Understanding this phenomenon is important for assessing the impact of radiation-related accidents, occupational exposures and space missions. In this context, in this study we analyzed the effect of gamma rays on the Antarctic cryptoendolithic melanized fungus Friedmanniomyces endolithicus CCFEE 5208 and demonstrated its resistance to acute doses of gamma radiation (up to 400 Gy), accompanied by increase in metabolic activity.
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http://dx.doi.org/10.1016/j.funbio.2018.10.002DOI Listing
December 2018

Survival, DNA, and Ultrastructural Integrity of a Cryptoendolithic Antarctic Fungus in Mars and Lunar Rock Analogs Exposed Outside the International Space Station.

Astrobiology 2019 02 30;19(2):170-182. Epub 2018 Oct 30.

4 Astrobiological Laboratories, Institute of Planetary Research, Management and Infrastructure, German Aerospace Center (DLR) Berlin, Berlin, Germany.

The search for life beyond Earth involves investigation into the responses of model organisms to the deleterious effects of space. In the frame of the BIOlogy and Mars Experiment, as part of the European Space Agency (ESA) space mission EXPOSE-R2 in low Earth orbit (LEO), dried colonies of the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 were grown on martian and lunar analog regolith pellets, and exposed for 16 months to LEO space and simulated Mars-like conditions on the International Space Station. The results demonstrate that C. antarcticus was able to tolerate the combined stress of different extraterrestrial substrates, space, and simulated Mars-like conditions in terms of survival, DNA, and ultrastructural stability. Results offer insights into the habitability of Mars for future exploration missions on Mars. Implications for the detection of biosignatures in extraterrestrial conditions and planetary protection are discussed.
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http://dx.doi.org/10.1089/ast.2017.1728DOI Listing
February 2019

Responses of the Black Fungus Cryomyces antarcticus to Simulated Mars and Space Conditions on Rock Analogs.

Astrobiology 2019 02 1;19(2):209-220. Epub 2018 Aug 1.

1 Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy.

The BIOMEX (BIOlogy and Mars Experiment) is part of the European Space Agency (ESA) space mission EXPOSE-R2 in Low-Earth Orbit, devoted to exposing microorganisms for 1.5 years to space and simulated Mars conditions on the International Space Station. In preparing this mission, dried colonies of the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515, grown on martian and lunar analog regolith pellets, were subjected to several ground-based preflight tests, Experiment Verification Tests, and Science Verification Tests (SVTs) that were performed to verify (i) the resistance of our model organism to space stressors when grown on extraterrestrial rock analogs and (ii) the possibility of detecting biomolecules as potential biosignatures. Here, the results of the SVTs, the last set of experiments, which were performed in ultraviolet radiation combined with simulated space vacuum or simulated martian conditions, are reported. The results demonstrate that C. antarcticus was able to tolerate the conditions of the SVT experiment, regardless of the substratum in which it was grown. DNA maintained high integrity after treatments and was confirmed as a possible biosignature; melanin, which was chosen to be a target for biosignature detection, was unambiguously detected by Raman spectroscopy.
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http://dx.doi.org/10.1089/ast.2016.1631DOI Listing
February 2019

Antarctic Cryptoendolithic Fungal Communities Are Highly Adapted and Dominated by Lecanoromycetes and Dothideomycetes.

Front Microbiol 2018 29;9:1392. Epub 2018 Jun 29.

Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy.

Endolithic growth is one of the most spectacular microbial adaptations to extreme environmental constraints and the predominant life-form in the ice-free areas of Continental Antarctica. Although Antarctic endolithic microbial communities are known to host among the most resistant and extreme-adapted organisms, our knowledge on microbial diversity and composition in this peculiar niche is still limited. In this study, we investigated the diversity and structure of the fungal assemblage in the cryptoendolithic communities inhabiting sandstone using a meta-barcoding approach targeting the fungal Internal Transcribed Sequence region 1 (ITS1). Samples were collected from 14 sites in the Victoria Land, along an altitudinal gradient ranging from 1,000 to 3,300 m a.s.l. and from 29 to 96 km distance to coast. Our study revealed a clear dominance of a 'core' group of fungal consistently present across all the samples, mainly composed of lichen-forming and Dothideomycetous fungi. Pareto-Lorenz curves indicated a very high degree of specialization (F approximately 95%), suggesting these communities are highly adapted but have limited ability to recover after perturbations. Overall, both fungal community biodiversity and composition did not show any correlation with the considered abiotic parameters, potentially due to strong fluctuations of environmental conditions at local scales.
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http://dx.doi.org/10.3389/fmicb.2018.01392DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033990PMC
June 2018

Integrity of the DNA and Cellular Ultrastructure of Cryptoendolithic Fungi in Space or Mars Conditions: A 1.5-Year Study at the International Space Station.

Life (Basel) 2018 Jun 19;8(2). Epub 2018 Jun 19.

Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.

The black fungi and are highly melanized and are resilient to cold, ultra-violet, ionizing radiation and other extreme conditions. These microorganisms were isolated from cryptoendolithic microbial communities in the McMurdo Dry Valleys (Antarctica) and studied in Low Earth Orbit (LEO), using the EXPOSE-E facility on the International Space Station (ISS). Previously, it was demonstrated that and survive the hostile conditions of space (vacuum, temperature fluctuations, and the full spectrum of extraterrestrial solar electromagnetic radiation), as well as Mars conditions that were simulated in space for a 1.5-year period. Here, we qualitatively and quantitatively characterize damage to DNA and cellular ultrastructure in desiccated cells of these two species, within the frame of the same experiment. The DNA and cells of exhibited a higher resistance than those of . This is presumably attributable to the thicker (melanized) cell wall of the former. Generally, DNA was readily detected (by PCR) regardless of exposure conditions or fungal species, but the DNA had been more-extensively mutated. We discuss the implications for using DNA, when properly shielded, as a biosignature of recently extinct or extant life.
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http://dx.doi.org/10.3390/life8020023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027225PMC
June 2018

Sun Exposure Shapes Functional Grouping of Fungi in Cryptoendolithic Antarctic Communities.

Life (Basel) 2018 Jun 2;8(2). Epub 2018 Jun 2.

Department of Ecological and Biological Sciences, University of Tuscia, Viterbo 01100, Italy.

Antarctic cryptoendolithic microbial communities dominate ice-free areas of continental Antarctica, among the harshest environments on Earth. The endolithic lifestyle is a remarkable adaptation to the exceptional environmental extremes of this area, which is considered the closest terrestrial example to conditions on Mars. Recent efforts have attempted to elucidate composition of these extremely adapted communities, but the functionality of these microbes have remained unexplored. We have tested for interactions between measured environmental characteristics, fungal community membership, and inferred functional classification of the fungi present and found altitude and sun exposure were primary factors. Sandstone rocks were collected in Victoria Land, Antarctica along an altitudinal gradient from 834 to 3100 m a.s.l.; differently sun-exposed rocks were selected to test the influence of this parameter on endolithic settlement. Metabarcoding targeting the fungal internal transcribed spacer region 1 (ITS1) was used to catalogue the species found in these communities. Functional profile of guilds found in the samples was associated to species using FUNGuild and variation in functional groups compared across sunlight exposure and altitude. Results revealed clear dominance of lichenized and stress-tolerant fungi in endolithic communities. The main variations in composition and abundance of functional groups among sites correlated to sun exposure, but not to altitude.
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http://dx.doi.org/10.3390/life8020019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027399PMC
June 2018

Resistance of an Antarctic cryptoendolithic black fungus to radiation gives new insights of astrobiological relevance.

Fungal Biol 2018 06 4;122(6):546-554. Epub 2017 Nov 4.

Department of Ecological and Biological Sciences (DEB), University of Tuscia, Largo dell'Università snc, 01100 Viterbo, Italy. Electronic address:

The Antarctic black meristematic fungus Cryomyces antarcticus CCFEE 515 occurs endolithically in the McMurdo Dry Valleys of Antarctica, one of the best analogue for Mars environment on Earth. To date, this fungus is considered one of the best eukaryotic models for astrobiological studies and has been repeatedly selected for space experiments in the last decade. The obtained results are reviewed here, with special focus on responses to space relevant irradiation, UV radiation, and both sparsely and densely ionizing radiation, which represent the major injuries for a putative space-traveller. The remarkable resistance of this model organism to space stress, its radioresistance in particular, and mechanisms involved, significantly contributed to expanding our concept of limits for life and provided new insights on the origin and evolution of life in planetary systems, habitability, and biosignatures for life detection as well as on human protection during space missions.
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http://dx.doi.org/10.1016/j.funbio.2017.10.012DOI Listing
June 2018

A thin ice layer segregates two distinct fungal communities in Antarctic brines from Tarn Flat (Northern Victoria Land).

Sci Rep 2018 04 26;8(1):6582. Epub 2018 Apr 26.

Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy.

Brines are hypersaline solutions which have been found within the Antarctic permafrost from the Tarn Flat area (Northern Victoria Land). Here, an investigation on the possible presence and diversity of fungal life within those peculiar ecosystems has been carried out for the first time. Brines samples were collected at 4- and 5-meter depths (TF1 and TF2, respectively), from two brines separated by a thin ice layer. The samples were analyzed via Illumina MiSeq targeting the ITS region specific for both yeasts and filamentous fungi. An unexpected high alpha diversity was found. Beta diversity analysis revealed that the two brines were inhabited by two phylogenetically diverse fungal communities (Unifrac value: 0.56, p value < 0.01; Martin's P-test p-value < 0.001) characterized by several specialist taxa. The most abundant fungal genera were Candida sp., Leucosporidium sp., Naganishia sp. and Sporobolomyces sp. in TF1, and Leucosporidium sp., Malassezia sp., Naganishia sp. and Sporobolomyces sp. in TF2. A few hypotheses on such differentiation have been done: i) the different chemical and physical composition of the brines; ii) the presence in situ of a thin layer of ice, acting as a physical barrier; and iii) the diverse geological origin of the brines.
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http://dx.doi.org/10.1038/s41598-018-25079-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5919928PMC
April 2018

The effect of protracted X-ray exposure on cell survival and metabolic activity of fast and slow growing fungi capable of melanogenesis.

Environ Microbiol Rep 2018 06 25;10(3):255-263. Epub 2018 Mar 25.

College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

The aim of this study was to analyse how protracted exposure to X-rays delivered at low dose rates of 0.0032-0.052 kGy h affects the survival and metabolic activity of two microfungi capable of melanogenesis: fast-growing Cryptococcus neoformans (CN) and slow-growing Cryomyces antarcticus (CA). Melanized CN and CA cells survived the protracted exposure better than non-melanized ones, which was consistent with previous reports on the radioprotective role of melanin in these fungi after high dose rate exposures. The survival data were described by the linear quadratic dose response model. The XTT metabolic profiles were practically identical for melanized CN and CA with activity dose-dependent increasing: no changes in the activity of the non-melanized CN and CA were recorded by this assay. In contrast, the MTT assay, which measures the intracellular energy-related processes, recorded an increase in activity of non-melanized CN and CA cells, but not in their melanized counterparts. This could reflect intensive repair processes initiated by the non-melanized cells post exposure. This study suggests that differences in radiation responses between melanized and non-melanized fungal cells occur over a wide range of radiation dose rates.
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http://dx.doi.org/10.1111/1758-2229.12632DOI Listing
June 2018

Cryptoendolithic Antarctic Black Fungus Irradiated with Accelerated Helium Ions: Survival and Metabolic Activity, DNA and Ultrastructural Damage.

Front Microbiol 2017 17;8:2002. Epub 2017 Oct 17.

Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy.

Space represents an extremely harmful environment for life and survival of terrestrial organisms. In the last decades, a considerable deal of attention was paid to characterize the effects of spaceflight relevant radiation on various model organisms. The aim of this study was to test the survival capacity of the cryptoendolithic black fungus CCFEE 515 to space relevant radiation, to outline its endurance to space conditions. In the frame of an international radiation campaign, dried fungal colonies were irradiated with accelerated Helium ion (150 MeV/n, LET 2.2 keV/μm), up to a final dose of 1,000 Gy, as one of the space-relevant ionizing radiation. Results showed that the fungus maintained high survival and metabolic activity with no detectable DNA and ultrastructural damage, even after the highest dose irradiation. These data give clues on the resistance of life toward space ionizing radiation in general and on the resistance and responses of eukaryotic cells in particular.
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http://dx.doi.org/10.3389/fmicb.2017.02002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5650992PMC
October 2017

Effect of environmental parameters on biodiversity of the fungal component in lithic Antarctic communities.

Extremophiles 2017 Nov 9;21(6):1069-1080. Epub 2017 Oct 9.

Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy.

A wide sampling of rocks, colonized by microbial epi-endolithic communities, was performed along an altitudinal gradient from sea level to 3600 m asl and sea distance from the coast to 100 km inland along the Victoria Land Coast, Antarctica. Seventy-two rock samples of different typology, representative of the entire survey, were selected and studied using denaturing gradient gel electrophoresis to compare variation in fungal diversity according to environmental conditions along this altitudinal and sea distance transect. Lichenized fungi were largely predominant in all the samples studied and the biodiversity was heavily influenced even by minimal local variations. The n-MDS analysis showed that altitude and sea distance affect fungal biodiversity, while sandstone allows the communities to maintain high biodiversity indices. The Pareto-Lorenz curves indicate that all the communities analyzed are highly adapted to extreme conditions but scarcely resilient, so any external perturbation may have irreversible effects on these fragile ecosystems.
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http://dx.doi.org/10.1007/s00792-017-0967-6DOI Listing
November 2017

Draft Genome Sequences of the Antarctic Endolithic Fungi CCFEE 5527 and sp. CCFEE 5018.

Genome Announc 2017 Jul 6;5(27). Epub 2017 Jul 6.

Department of Plant Pathology and Microbiology and Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, USA

The draft genome sequences of CCFEE 5527 and sp. CCFEE 5018 are the first sequenced genomes from this genus, which comprises rock-inhabiting fungi. These endolithic strains were isolated from inside rocks collected from the Antarctic Peninsula and Battleship Promontory (McMurdo Dry Valleys), Antarctica, respectively.
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http://dx.doi.org/10.1128/genomeA.00397-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5502844PMC
July 2017

Survival, DNA Integrity, and Ultrastructural Damage in Antarctic Cryptoendolithic Eukaryotic Microorganisms Exposed to Ionizing Radiation.

Astrobiology 2017 02 2;17(2):126-135. Epub 2017 Feb 2.

1 Department of Ecological and Biological Sciences, University of Tuscia , Viterbo, Italy .

Life dispersal between planets, planetary protection, and the search for biosignatures are main topics in astrobiology. Under the umbrella of the STARLIFE project, three Antarctic endolithic microorganisms, the melanized fungus Cryomyces antarcticus CCFEE 515, a hyaline strain of Umbilicaria sp. (CCFEE 6113, lichenized fungus), and a Stichococcus sp. strain (C45A, green alga), were exposed to high doses of space-relevant gamma radiation (Co), up to 117.07 kGy. After irradiation survival, DNA integrity and ultrastructural damage were tested. The first was assessed by clonogenic test; viability and dose responses were reasonably described by the linear-quadratic formalism. DNA integrity was evaluated by PCR, and ultrastructural damage was observed by transmission electron microscopy. The most resistant among the tested organisms was C. antarcticus both in terms of colony formation and DNA preservation. Besides, results clearly demonstrate that DNA was well detectable in all the tested organisms even when microorganisms were dead. This high resistance provides support for the use of DNA as a possible biosignature during the next exploration campaigns. Implication in planetary protection and contamination during long-term space travel are put forward. Key Words: Biosignatures-Ionizing radiation-DNA integrity-Eukaryotic microorganisms-Fingerprinting-Mars exploration. Astrobiology 17, 126-135.
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http://dx.doi.org/10.1089/ast.2015.1456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5314979PMC
February 2017
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