Sieglinde Ott

Heinrich-Heine-Universität Düsseldorf | HHU · Department of Biology

As part of the Biology and Mars Experiment (BIOMEX; ILSRA 2009-0834), samples of the lichen Circinaria gyrosa were placed on the exposure platform EXPOSE-R2, on the International Space Station (ISS) and exposed to space and to a Mars-simulated environment for 18 months (2014-2016) to study: (1) resistance to space and Mars-like conditions and (2) b...

As part of the Biology and Mars Experiment (BIOMEX; ILSRA 2009-0834), samples of the lichen Circinaria gyrosa were placed on the exposure platform EXPOSE-R2, on the International Space Station (ISS) and exposed to space and to a Mars-simulated environment for 18 months (2014–2016) to study: (1) resistance to space and Mars-like conditions and (2) b...

As part of the ESA space experiment BIOMEX (Biology and Mars Experiment) the lichen Buellia frigida has been exposed to space and simulated Mars analogue conditions on the expose facility EXPOSE-R2 placed outside the Russian Zvezda module on the International Space Station (ISS) for 1.5 years. Randomly Amplified Polymorphic DNA (RAPD) technique has...

The vegetation of many terrestrial habitats across Antarctica is dominated by poikilohydric symbiotic lichens. Terrestrial habitats generally are characterised by extended exposure to desiccation and high irradiation. Physiological adaptation mechanisms of the algal partner (photobiont) are key factors in the successful colonisation of lichens of l...

The lichen Buellia frigida was exposed to space and simulated Mars analog conditions in the Biology and Mars Experiment (BIOMEX) project operated outside the International Space Station (ISS) for 1.5 years. To determine the effects of the Low Earth Orbit (LEO) conditions on the lichen symbionts, a LIVE/DEAD staining analysis test was performed. Aft...

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 biosign...

Exploration of the solar system is a priority research area of the AstRoMap European Astrobiology Roadmap (Horneck et al., 2015) [1], focused on various research topics, one of them is “Life and Habitability” and an other one is “Biomarkers for easy the detection of life”. Therefore “space platforms and laboratories” are necessary, such as EXPOSE,...

Premise of the study Usnea antarctica and U. aurantiacoatra (Parmeliaceae) are common lichens in the maritime Antarctic. These species share the same habitats on King George Island (South Shetland Islands, Antarctica) and are distinguishable based on reproductive strategies. Methods and Results We developed 23 fungus-specific simple sequence repea...

The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disc...

This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113...

Antarctic ice-free inland sites provide a unique perspective on the strategies coevolving organisms have developed for survival at the limits of life. Here, we provide the first combined description of the ecological and genetic diversity of lichen photobionts colonising an isolated Antarctic inland site, Coal Nunatak, on south-east Alexander Islan...

Desiccation tolerance is a feature of most lichens. These symbiotic associations of a fungal partner (mycobiont) and a photosynthetic partner (photobiont) experience severe desiccation on a regular basis. Many lichen species colonise extreme habitats, such as the cold deserts of Antarctica. Although the stress physiology of lichens has been studied...

• Premise of the study: Polymorphic microsatellite markers were developed for the lichen species Cetraria aculeata (Parmelia- ceae) to study fine-scale population diversity and phylogeographic structure. • Methods and Results: Using Illumina HiSeq and MiSeq, 15 fungus-specific microsatellite markers were developed and tested on 81 specimens from fo...

The lichen Xanthoria elegans has been exposed to space and simulated Mars-analogue environment in the Lichen and Fungi Experiment (LIFE) on the EXPOSE-E facility at the International Space Station (ISS). This long-term exposure of 559 days tested the ability of various organisms to cope with either low earth orbit (LEO) or Mars-analogue conditions,...

Samples of the extremotolerant Antarctic endemite lichen Buellia frigida are currently exposed to low-Earth orbit-space and simulated Mars conditions at the Biology and Mars Experiment (BIOMEX), which is part of the ESA mission EXPOSE-R2 on the International Space Station and was launched on 23 July 2014. In preparation for the mission, several pre...

Lichens as symbiotic associations consisting of a fungus (the mycobiont) and a photosynthetic partner (the photobiont) dominate the terrestrial vegetation of continental Antarctica. The photobiont provides carbon nutrition for the fungus. Therefore, performance and protection of photosystem II is a key factor of lichen survival. Potentials and limi...

In the past decade, various astrobiological studies on different lichen species investigated the impairment of viability and photosynthetic activity by exposure to simulated or real space parameters (as vacuum, polychromatic ultraviolet (UV)-radiation and monochromatic UVC) and consistently found high post-exposure viability as well as low rates of...

Ground simulation tests are necessary for selection of the most promising biological organisms for flight experiments in Low Earth Orbit or other space destinations: Simulation of the environmental parameters of the mission, as well as of sample assembly and disassembly, need to be performed, allowing the qualification of the experiment and facilit...

Previous studies investigated the viability and photosynthetic activity of lichen photobionts after exposure to simulated or real space parameters. They consistently found high viability and recovery of photosynthetic activity (de Vera et al. 2003, 2004a, 2004b, de la Torre et al. 2010, Onofri et al. 2012, Sánchez et al. 2012, 2014, Brandt et al. 2...

In the Lichen and Fungi Experiment (LIFE) the lichen Xanthoria elegans demonstrated considerable resistance to space and simulated Mars-analogue conditions being exposed on the International Space Station. This first European long-term exposure (559 days) of eukaryotic organisms tested their ability to cope with the combined hostile conditions of s...

The lichen Xanthoria elegans has been exposed to space conditions and simulated Mars-analogue conditions in the lichen and fungi experiment (LIFE) on the International Space Station (ISS). After several simulations and short space exposure experiments such as BIOPAN, this was the first long-term exposure of eukaryotic organisms to the hostile space...

New results on extremophiles and observations of Mars missions regarding the detailed mineralogy, the occurrence of water in the equatorial region of Mars [1-3], new announcements of MSL findings and their implications for the surface condi-tions at Gale crater [4, 5] as well as measurements of the Mars surface radiation environment [6] fuel the de...

Many experiments were carried out in order to evaluate the survival capacity of extremotolerant lichens when facing harsh conditions, including those of outer space or of simulated Martian environment. For further progress, a deeper study on the physiological mechanisms is needed that confer the unexpected levels of resistance detected on these sym...

One important mechanism for understanding the interaction between cells and the various radiation sources in space is to perform laboratory analysis on microorganisms or bio-relevant molecules which have been exposed to this radiation environment. However comprehensive scientific assessment of the biological effects caused by exposure to real space...

Lichens, which are symbioses of a fungus and one or two photoautotrophs, frequently tolerate extreme environmental conditions. This makes them valuable model systems in astrobiological research to fathom the limits and limitations of eukaryotic symbioses. Various studies demonstrated the high resistance of selected extremotolerant lichens towards e...

Lichens are symbioses of two organisms, a fungal mycobiont and a photoautotrophic photobiont. In nature, many lichens tolerate extreme environmental conditions and thus became valuable models in astrobiological research to fathom biological resistance towards non-terrestrial conditions; including space exposure, hypervelocity impact simulations as...

The flora of continental Antarctica is dominated by lichens. These symbiotic associations consist of a fungus (the mycobiont) and a green alga or cyanobacterium (the photobiont) essential for carbon nutrition of the symbiotic organisms. Lichen thalli occur in crustose and more complex growth forms. In non-crustose species (macrolichens) of continen...

Successful re-lichenization between the two bionts of the lichen symbiosis, the fungal mycobiont and its specific photobiont, is a process that is not well understood yet. To assess potential signalling between the two bionts during initial pre-contact, exudates of the Trebouxia photobionts of Fulgensia bracteata, Fulgensia fulgens, and Xanthoria e...

Lichens are an association of a photoautotrophic alga/cyanobacteria (photobiont) and a heterotrophic fungus (mycobiont) constituting the lichen thallus as a complex phenotype. Many mycobionts reproduce sexually and the ascospores are dispersed without the photobiont. For successful re-lichenization the specific photobiont must be recognized, contac...

A quantitative study is presented of the water vapor interaction with extremophiles under close to martian surface conditions using adsorption methods.

Lichens form an important part of the biodiversity in terrestrial ecosystems of Antarctica where they represent the dominant vegetation. Previous studies on the genetic diversity of photobionts of lichens have indicated that clade S Trebouxia photobionts are the most widespread in continental Antarctica, predominantly in macrolichens. For the first...

The “Planetary Atmospheres and Surfaces Chamber” (PASC, at Centro de Astrobiología, INTA, Madrid) is able to simulate the atmosphere and surface temperature of most of the solar system planets. PASC is especially appropriate to study irradiation induced changes of geological, chemical, and biological samples under a wide range of controlled atmosph...

Cryptoendolithic microbial communities and epilithic lichens have been considered as appropriate candidates for the scenario of lithopanspermia, which proposes a natural interplanetary exchange of organisms by means of rocks that have been impact ejected from their planet of origin. So far, the hardiness of these terrestrial organisms in the severe...

RLS (Raman Laser Spectrometer - one of the Pasteur Payload Instruments onboard ExoMars 2018) will perform Raman measurements on Mars to identify organic compounds and mineral products as an indication of biological activity. The measurements will be performed on crushed powdered samples inside the Rover's ALD (Analytical Laboratory Drawer). Raman...

The Holarctic fruticose lichen Stereocaulon paschale is known to be capable of tolerating at least six weeks of constant submersion under natural conditions in a meltwater pool at about 1000 m above sea level in Rondane in eastern Norway. Its adaptations to temporary submergence involve both physiology and anatomy, differing fundamentally from Clad...

Cryptoendolithic microbial communities and epilithic lichens have been considered as appropriate candidates for the scenario of lithopanspermia, which proposes a natural interplanetary exchange of organisms by means of rocks that have been impact ejected from their planet of origin. So far, the hardiness of these terrestrial organisms in the severe...

Shock recovery experiments were performed with an explosive set-up in which three types of microorganisms embedded in various types of host rocks were exposed to strong shock waves with pressure pulse lengths of lower than 0.5 ls: spores of the bacterium Bacillus subtilis, Xanthoria elegans lichens, and cells of the cyanobacterium Chroococcidiopsis...

A possible source of Trebouxia algae for lichens are the thalli of lichens that are attacked by another mycobiont that captures the algae for its own symbiotic use. Such a process is described for Fulgensia bracteata living in parasitic association with Toninia caeruleonigricans. The development of the thalli of Toninia and the parasitic attack of...

Carbon isotope data suggest that microbial life was present on Earth as early as 3.5 Ga ago, and probably even 4 Ga ago, and indicates that biological CO2 fixation was an early feature (Schidlowski, 2001). The early biosphere was dominated by microbial life forms for a long period, during which they evolved to exploit new niches. For some, this inv...

In the space experiments Lithopanspermia, experimental support was provided to the likelihood of the lithopanspermia concept that considers a viable transport of microorganisms between the terrestrial planets by means of meteorites. The rock colonising lichens Rhizocarpon geographicum and Xanthoria elegans, the vagrant lichen Aspicilia fruticulosa,...

Coal Nunatak is an ice-free inland nunatak located on southern Alexander Island, adjacent to the west coast of the Antarctic Peninsula. Situated close to the Antarctic continent, it is characterized by harsh environmental conditions. Macroscopic colonization is restricted to micro-niches offering suitable conditions for a small number of lichens an...

During the EXPOSE-LIFE-Experiment lichens, antarctic microfungi and rocks colonized by microorganisms have been exposed for 18 months on the ISS. The first results indicated survival and maintenance of metabolic activity.

Lichens were repetitively exposed over 22 days to thermophysical Mars-like conditions at low-and mid-latitudes. The simulated parameters and the experimental setup are described. Natural samples of the lichen Xanthoria elegans were used to investigate their ability to survive the applied Mars-like conditions. The effects of atmospheric pressure, CO...

Extremophiles are microorganisms, which are liv-ing in extreme habitats. The environmental condi-tions in these habitats are very harsh. They can be characterised by very low or high temperatures, high radiation fluxes, low water availability up to total dryness, high salinity and very low or very high pH-values. Extremophiles are specialists which...

A characterisation of a global transect of lichen habitats from the European Alps to Mediterranean Mountain region and to the North Victoria Land Mountains in Antarctica shows the adaptation and colonizing strategies of these symbiotic microorganisms in extreme environments which are often described as Mars analogue areas. Numerous lichens are able...

Extremophiles are specialists which colonise special niches in these extreme environments due to there adaptation capacities attained during the evolution of life. Some examples of extremophiles and their potential to deal with harsh conditions as well as the characterisation of their niches will be presented. Based on observations and results obta...

The experiment Lithopanspermia and the experiment Life: The concept of both of the space experiments is to expose different eukaryotic species as there are the lichens Xanthoria elegans, Rhizocarpon geographicum and their mycobiont cultures, the black Antarctic microfungi Cryomyces minteri and Cryomyces antarcticus and Antarctic rocks colonized by...

The experiment Lithopanspermia and the experiment Life: The concept of both of the space experiments is to expose different eukaryotic species as there are the lichens Xan-thoria elegans, Rhizocarpon geographicum and their mycobiont cultures, the black Antarctic microfungi Cryomyces minteri and Cryomyces antarcticus and Antarctic rocks colonized by...

Inland Antarctic nunataks typically have simple physically weathered soils and limited ecosystem complexity. In this paper we present quantitative measurements of soil physical and chemical properties at one Antarctic nunatak. We measured pH, grain size, field capacity, soil organic carbon, phosphate, nitrate, ammonium and the cations magnesium, ca...

Lichens are described as a symbiosis formed by a myco- and photobiont, capable of colonizing habitats where their separate symbionts would not be able to survive. Space simulation studies on the separated symbionts of the lichen Xanthoria elegans have been performed to test their capacity to resist the most extreme conditions. The isolated cultured...

Juvenile development from sown vegetative diaspores of the cyanobacterial lichen Lobaria scrobiculata and the green algal lichens Platismatia glauca and P. norvegica was studied through a four-year field experiment in a boreal spruce forest. All three species developed juvenile thalli within the period of observation. The largest lobules of L. scro...

OTT, S., TREIBER, K. & JAHNS, H.M., 1992. The development of regenerative thallus structures in lichens. To be successful in their symbiotic relationship lichens have developed generative and regenerative thallus structures. Examples of the latter include isidia and soredia. In connection with the fact that construction principles in the lichen tha...

Thalli of Xanthoria parietina have been grown in cultures in the natural environment. In early phases of development the fungus associates with foreign algae and only later forms a symbiosis with Pseudotrebouxia. The lichen is shown to have a very effective mechanism for distribution by sexual spores followed by relichenization.

The scenario of lithopanspermia describes the viable transport of microorganisms via meteorites. To test the first step of lithopanspermia, i.e., the impact ejection from a planet, systematic shock recovery experiments within a pressure range observed in martian meteorites (5-50 GPa) were performed with dry layers of microorganisms (spores of Bacil...

Inland Antarctic terrestrial ecosystems and biodiversity are poorly understood in comparison with Antarctic coastal regions. Microorganisms, as primary colonists, are integral to Antarctic soil ecosystem development, essential for pedogenesis and structuring the soil, and providing the nutrients necessary for the subsequent establishment of macroor...

Understanding the role of microbe-mineral interactions in rock weathering is vital to an understanding of nutrient availability to the biosphere and, in so far as weathering influences carbon dioxide drawdown, climate control. We studied a weathering crust on a resurge tsunami deposit (Loftarstone) from the 455 Ma old Lockne impact crater, central...

About 200 million years ago (MYA), the Antarctic continent formed, together with Australia, Africa, South America, India and New Zealand, the supercontinent Gondwana. As the supercontinent broke up, giving the continents with which we are familiar today, Antarctica finally lost contact with Australia (c.45-50MYA) and South America (c. 30MYA). Throu...

Petrographic and biological analysis of shock recovery experiments confirms the possible life transport due to an impact from Mars to Earth.

Bacterial spores (Bacillus subtilis), cyanobacteria (Chroococcidiopsis sp.), and lichen (Xanthoria elegans) embedded in martian analogue rock (gabbro) were exposed to shock pressures between 5 and 50 GPa which is the range of pressures observed in martian meteorites. The survival of Bacillus subtilis and Xanthoria elegans up to 45 GPa and of Chrooc...

Bacterial spores (Bacillus subtilis), cyanobacteria (Chroococcidiopsis sp.), and lichen (Xanthoria elegans) embedded in martian analogue rock (gabbro) were exposed to shock pressures between 5 and 50 GPa which is the range of pressures observed in martian meteorites. The survival of Bacillus subtilis and Xanthoria elegans up to 45 GPa and of Chrooc...

Lichens are symbiotic organisms associated by a fungus (mycobiont) and a a photosynthetic biont. As a consequence of the symbiotic state both the bionts are able to colonise habitats where the separate bionts would not be able to survive. The symbiosis of lichens reflects a high degree of complexity and plasticity. The combination of the different...

Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microorganisms reveal that these organisms survive the impact and ejection phase on Mars at shock pressures up to about 50 GPa with exponentially decreasing survival rates.

Complementary to the already well-studied microorganisms, lichens, symbiotic organisms of the mycobiont (fungi) and the photobiont (algae), were used as "model systems" in which to examine the ecological potential to resist to extreme environments of outer space. Ascospores (sexual propagules of the mycobiont) of the lichens Fulgensia bracteata, Xa...

Juvenile development has been investigated for the first time in an Antarctic lichen species-Usnea antarctica-in the northern maritime Antarctic, Livingston Island (South Shetland Islands, 62degrees27'-62degrees48'S, 59degrees45'-61degrees15'W). Here, U. antarctica grows on rocks and forms the dominant vegetation on this site together with a few ot...

The Antarctic endemics Umbilicaria kappenii and U. antarctica are morphologically close, but mainly distinguished by their reproductive strategies. Umbilicaria antarctica propagates by means of thalloconidia. Umbilicaria kappenii lacks thalloconidia, but exhibits a variety of asexual propagules: soredia, adventive lobes and thallyles. We have now e...

A lichen is a symbiotic association formed by a mycobiont (fungi), a photobiont (algae) and/or a cyanobacteria. The special symbiotic contact and interaction between the bionts in a lichen is a prerequisite for maintainance of viability for each of them during influences by harsh environmental factors. In nature parameters like UV radiation, low or...

Himantormia lugubris has developed special growth strategies as well as special structures on morphology and anatomy. H. lugubris, an antarctic endemic, is distributed on the islands of the northern maritime Antarctic and along the Antarctic Peninsula (to the Argentine Islands). The rock surface is colonized by a thin web of hyphae from which a hor...

: Lichen communities are characterised by interspecific interactions that not only include interactions between different lichen species but also between the symbionts within a single lichen species. The community “Bunte Erdflechtengesellschaft”, growing on weathered calciferous rocks known as Gravel Alvar on Gotland (Baltic Sea, Sweden), shows a h...

The lichen symbiotic organisms Fulgensia bracteata and Xanthoria elegans as well as their isolated photobionts and mycobionts were exposed to conditions simulating the extreme parameters of outer space in order to assess their limits of survival, e.g. during a potential interplanetary transfer or on the surface of an extraterrestrial body. Using th...

Lichens from the genus Umbilicaria were collected across a 5,000-km transect through Antarctica and investigated for DNA sequence polymorphism in a region of 480-660 bp of the nuclear internal transcribed spacer region of ribosomal DNA. Sequences from both fungal (16 ascomycetes) and photosynthetic partners (22 chlorophytes from the genus Trebouxia...

As a consequence of the symbiotic state of lichens both the bionts are able to colonize habitats where the separate bionts would not be able to survive. The symbiosis of lichens reflects a high degree of complexity and plasticity. The combination of the different bionts enables these organisms to colonize most extreme habitats worldwide from the Ar...

The distribution of plants and the development of individuals at a certain location depend to a considerable degree upon microclimate. This is true for phanerogams as well as for lichens. For lichens, however, crucial environmental influences occur on a much smaller scale (Schöller 1991, Canters et al. 1991). The microclimate of a higher plant is d...

Much research has been done on plant hormones in higher plants, where they play a fundamental role in regulating plant growth, development and reproduction (Davies 1995). In addition, in lichens interactions between the mycobiont and the photobiont require regulation (Jahns and Ott 1990). Plant hormones are a group of natural organic substances tha...

When the symbiotic nature of lichens was discovered, scientists attempted to culture these organisms. As the lichens consist of a mycobiont and a photobiont, an obvious aim was to separate the two partners and then resynthesise intact lichens. Later experiments included the culturing of isolated symbionts (Ahmadjian 1973, 1989, Bubrick & Galun 1988...

In the lichen symbiosis growth processes, morphogenesis and reproduction are characterized by a system of complicated interactions. For regulation of these complex interactions between the bionts involved in the symbiosis phytohormones appear to play an important role. The study reports on the phytohormones IAA, ABA and ethylene in a great variety...

The symbiotic nature of the association between mycobiont and photobiont in the Antarctic lichen Turgidosculum complicatulum has been questioned. Some authors consider the lichen T. complicatulum to be an alga parasitized by the fungus. The photobiont Prasiola crispa ssp. antarctica (Kutzing) Knebel also occurs free-living in adjacent microhabitats...

Mycobionts of the four lichen species Anaptychia ciliaris, Physcia tenella, Physconia distorta and Xanthoria parietina, which were grown for more than one year under axenic conditions, were then attached to twigs of Quercus robur. The mycelia were subsequently exposed to natural conditions for one year. The observations show, that the isolated lich...

A wide range of taxa in the higher ascomycetes (Pezizomycotina sensu Eriksson and Winka 1997) forms some sort of symbiosis with algae and cyanobacteria. These associations include fungal parasites on algae (Hawksworth 1987; Lewin 1995), mycophycobioses (Kohlmeyer 1967; Kohlmeyer and Kohlmeyer 1972), lichenicolous fungi (Hawksworth 1983, 1988a; Clau...

: The symbiotic interactions in connection with the growth strategy of the crustose lichen Ochrolechia frigida (Sw.) Lynge have been investigated and the flexibility of its life strategies is discussed. The lichen is an interesting model organism for the mutualistic adaptation of bionts to each other and to the habitat conditions. O. frigida consis...

A specific lectin was isolated from cephalodiate thallus lobes of the lichen Peltigera aphthosa and purified to homogeneity by two steps: Chromatography on carboxymethyl-cellulose (CMC); and affinity chromatography on a lactose agarose column. TEM immunogold labeling using antibodies raised against the lectin, revealed a clear gold labeling of fung...

Plant communities of the rock-alvar of Gotland show a distinct pattern of distribution for a number of lichens and mosses. The microclimate of open concave rock flats, of aggregated moss-cushions, and of shaded areas beneath bushes is recorded. The species are adapted to complex interactions of external climatic factors. Distribution is influenced...

The vegetation of the rock-alvar of Gotland is characterized by a mosaic of herbaceous and shrubby vegetation and is dominated by small associations of mosses and lichens. The alvar has a maritime climate but with a continental influence producing frequent dry periods. Drainage is poor and dry periods are followed by flooding. The investigations re...