Ralf Moeller

German Aerospace Center (DLR) | DLR · Abteilung für Radiation Biology

Vancomycin-resistant Enterococcus faecium (VRE) presents significant challenges in healthcare, particularly for hospitalized and immunocompromised patients, including astronauts with dysregulated immune function. We investigated 42 clinical E. faecium isolates in simulated microgravity (sim. µg) using a 2-D Clinostat, with standard gravity conditio...

Aquatic ecosystems house a significant fraction of Earth’s biosphere, yet most prokaryotes inhabiting these environments remain uncultivated. While recently developed genome-resolved metagenomics and single-cell genomics techniques have underscored the immense genetic breadth and metabolic potential residing in uncultivated Bacteria and Archaea, cu...

ZUSAMMENFASSUNG Mikroorganismen begleiten uns in unserem Alltag als essenzieller Teil des menschlichen Körpers und der von uns bewohnten Lebensräume. Während viele der Mikroorganismen für uns Menschen nützlich sind, können einige von ihnen Infektionen verursachen. Die einzigartigen Bedingungen, die während Raumfahrtmissionen vorliegen, wirken sich...

On-demand biomanufacturing has the potential to improve healthcare and self-sufficiency during space missions. Cell-free transcription and translation reactions combined with DNA blueprints can produce promising therapeutics like bacteriophages and virus-like particles. However, how space conditions affect the synthesis and self-assembly of such co...

When we humans travel, our microorganisms come along. These can be harmless but also pathogenic, and are spread by touching surfaces or breathing aerosols in the passenger cabins. As the pandemic with SARS-CoV-2 has shown, those environments display a risk for infection transmission. For a risk reduction, countermeasures such as wearing face masks...

Quickly identifying and characterizing isolates from extreme environments is currently challenging while very important to explore the Earth′s biodiversity. As these isolates may, in principle, be distantly related to known species, techniques are needed to reliably identify the branch of life to which they belong. Proteotyping these environmental...

Common sterilization techniques for labile and sensitive materials have far-reaching applications in medical, pharmaceutical, and industrial fields. Heat inactivation, chemical treatment, and radiation are established methods to inactivate microorganisms, but pose a threat to humans and the environment and can damage susceptible materials or produc...

Presented poster at the 2023 ASGSR Annual Meeting. Agenda can be found here: https://asgsr.org/2023-meeting/#Program

High levels of carbon dioxide are known to inhibit the growth of microorganisms. A total of twenty strains of filamentous fungi and yeasts were isolated from habitats with enriched carbon dioxide concentration. Most strains were derived from modified atmosphere packed (MAP) food products or mofettes and were cultivated under an atmosphere of 20% CO...

Introduction Staphylococcus capitis naturally colonizes the human skin but as an opportunistic pathogen, it can also cause biofilm-associated infections and bloodstream infections in newborns. Previously, we found that two strains from the subspecies S. capitis subsp. capitis produce yellow carotenoids despite the initial species description, repor...

Simple Summary The Antarctic Polar Plateau is one of the most extreme environments on Earth and our knowledge on the microbial diversity inhabiting this region is still limited. The BacFinder project investigated microbial diversity on the snow surface of the Polar Plateau, focusing on the vicinity of the Concordia Antarctic Research Station, to as...

Melanins are complex pigments with various biological functions and potential applications in space exploration and biomedicine due to their radioprotective properties. Aspergillus niger, a fungus known for its high radiation resistance, is widely used in biotechnology and a candidate for melanin production. In this study, we investigated the produ...

The main objective of the ongoing and future space exploration missions is the search for traces of extant or extinct life (biomarkers) on Mars. One of the main limiting factors on the survival of Earth-like life is the presence of harmful space radiation, that could damage or modify also biomolecules, therefore understanding the effects of radiati...

Cyanobacteria are gaining considerable interest as a method of supporting the long-term presence of humans on the Moon and settlements on Mars due to their ability to produce oxygen and their potential as bio-factories for space biotechnology/synthetic biology and other applications. Since many unknowns remain in our knowledge to bridge the gap and...

On a future lunar habitat, acquiring needed resources in situ will inevitably come from the Lunar regolith. Biomining-the use of microorganisms to extract metals from the regolith-is sustainable and energy-efficient, making it highly promising for space exploration applications. Given the extensive use of filamentous fungi in industrial biotechnolo...

The Concordia Research Station provides a unique location for preparatory activities for future human journey to Mars, to explore microbial diversity at subzero temperatures, and monitor the dissemination of human-associated microorganisms within the pristine surrounding environment. Amplicon sequencing was leveraged to investigate the microbial di...

On-demand biomanufacturing has the potential to improve healthcare and self-sufficiency during space missions. Cell-free transcription and translation reactions combined with DNA blueprints can produce promising therapeutics like bacteriophages and virus-like particles. However, how space conditions affect the synthesis and self-assembly of such co...

Previous studies have reported that spaceflight specific conditions such as microgravity lead to changes in bacterial physiology and resistance behavior including increased expression of virulence factors, enhanced biofilm formation and decreased susceptibility to antibiotics. To assess if spaceflight induced physiological changes can manifest in h...

In the last decades, Mars has been widely studied with on-site missions and observations, showing a planet that could have hosted life in the past. For this reason, the recent and future space missions on the red planet will search for traces of past and, possibly, present life. As a basis for these missions, Space Agencies, such as the European Sp...

The effect of a Mars-like UV flux and γ-radiation on the detectability of biomarkers in dried cells of Chroococcidiopsis sp. CCMEE 029 was investigated using a fluorescence sandwich microarray immunoassay. The production of anti-Chroococcidiopsis antibodies allowed the immunoidentification of a reduced, though still detectable, signal in dried cell...

The biotechnology- and medicine-relevant fungus Aspergillus niger is a common colonizer of indoor habitats such as the International Space Station (ISS). Being able to colonize and biodegrade a wide range of surfaces, A. niger can ultimately impact human health and habitat safety. Surface contamination relies on two key-features of the fungal colon...

The question about the stability of certain biomolecules is directly connected to the life-detection missions aiming to search for past or present life beyond Earth. The extreme conditions experienced on extraterrestrial planet surface ( e.g. Mars), characterized by ionizing and non-ionizing radiation, CO 2 -atmosphere and reactive species, may des...

Biofilms are problematic on Earth due to their ability to both degrade the materials upon which they grow and promote infections. Remarkably, 65% of infections and 80% of chronic diseases on Earth are associated with biofilms. The impact of biofilms is even greater in space, as the crew's lives and mission success depend on nominal operation of mec...

BIOLEX (BIOlogy and Lunar EXperiments) tries to fulfil a large number of scientific investigations in reference to Astrobiology and Space Life Sciences. In situ Measurement operations through spectrometers (such as Raman, IR, UV/VIS and environmental sensors) on an exposure platform designed as a LOGOS cube (Lunar Organisms, Geo-microbiology and Or...

When the Artemis missions launch, NASA's Orion spacecraft (and crew as of the Artemis II mission) will be exposed to the deep space radiation environment beyond the protection of Earth's magnetosphere. Hence, it is essential to characterize the effects of space radiation, microgravity, and the combination thereof on cells and organisms, i.e., to qu...

Metal complexes of porphyrins and porphyrin-type compounds are ubiquitous in all three domains of life, with hemes and chlorophylls being the best-known examples. Their diagenetic transformation products are found as geoporphyrins, in which the characteristic porphyrin core structure is retained and which can be up to 1.1 billion years old. Because...

If life ever appeared on Mars and if it did refuge into sub-superficial environments when surface conditions turned too hostile, then it should have been periodically revived from the frozen, dormant state in order to repair the accumulated damage and reset the survival clock to zero for the next dormant phase. Thus, unravelling how long Earth dorm...

Microbial biofilms are universally present in our environment. However, biofilms can be problematic since they can damage materials and pose a health risk. Especially during space travel, where crew health is top priority and failure of equipment is detrimental, methods for preventing biofilm formation are vital. Antimicrobial active metals, such a...

The World Health Organization listed vancomycin-resistant enterococci (VRE) within high priority on the global list of antibiotic resistant bacteria, which prioritizes the development and research of novel antibiotics. As a cause of endemic hospital outbreaks worldwide, VRE emerged as nosocomial pathogens, which can cause severe infections like bac...

Maintaining crew health and safety are essential goals for long-term human missions to space. Attaining these goals requires the development of methods and materials for sustaining the crew’s health and safety. Paramount is microbiological monitoring and contamination reduction. Microbial biofilms are of special concern, because they can cause dama...

Viruses constitute a significant part of the human microbiome, so wherever humans go, viruses are brought with them, even on space missions. In this mini review, we focus on the International Space Station (ISS) as the only current human habitat in space that has a diverse range of viral genera that infect microorganisms from bacteria to eukaryotes...

A major concern during human space missions is microbial contamination. Biofilms are of particular importance as a potential hazard because they damage equipment and pose a health risk to astronauts. Biofilm formation can be inhibited by using antimicrobial active metals such as copper for contact surfaces. Previous studies have shown that the effi...

As space agencies plan to expand human presence in space and to settle on the Moon first and Mars later, developing strategies to achieve this goal in a sustainable way is necessary. These include in situ resource utilization (ISRU) and recovering of materials by waste recycling (1). Microbe based technologies may be pivotal to the success of human...

Radiation of ionizing or non-ionizing nature has harmful effects on cellular components like DNA as radiation can compromise its proper integrity. To cope with damages caused by external stimuli including radiation, within living cells, several fast and efficient repair mechanisms have evolved. Previous studies addressing organismic radiation toler...

Introduction: Long-term space missions are accompanied by harmful environmental conditions like microgravity. Due to the reduced gravity, astronauts adapt to their environment resulting in tissue fluidic shifts. Since the knowledge about microbiome data in space is sparse and conduction of experiments at the ISS is complex, suitable analogs are nee...

Long term human space missions require efficient strategies to sustain crew health and safety. This is why we need to develop improved spaceflight-suitable methods for microbiological monitoring and contamination control. Especially microbial biofilms are of concern in spaceflight because they can damage equipment by polymer deterioration, corrode...

As humans explore and settle in space, they will need to mine elements to support industries such as manufacturing and construction. In preparation for the establishment of permanent human settlements across the Solar System, we conducted the ESA BioRock experiment on board the International Space Station to investigate whether biological mining co...

In article 2001656, Daniel W. Müller and co‐workers were able to significally enhance antibacterial efficiency of Cu surfaces against Escherichia coli by ultrashort pulsed laser interference patterning in the scale of single bacteria cells. Improved bacterial killing could mainly be attributed to increased Cu sensitivity due to altered contact situ...

Remarkably, we know more about the radiation environment onboard the International Space Station than we do about radiation values at altitudes between 30-40 km in the middle stratosphere. Within this work, we provide data about the radiation dose measured during two consecutive balloon flights flown within a 4-month timeframe over New Mexico and A...

The ability of terrestrial life to survive in the Martian environment is of particular interest for both planetary protection measures and for future colonization endeavors. Many studies have examined bacterial spore survival and decontamination, however, little is known about fungal spore resistance properties. To understand the survival potential...

Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial survival potential in Mars-like conditions, several fungal and bacterial samples were launched in September 2019 on a large NASA scientific balloon flight to the middle stratosphere...

Copper (Cu) exhibits great potential for application in the design of antimicrobial contact surfaces aiming to reduce pathogenic contamination in public areas as well as clinically critical environments. However, current application perspectives rely purely on the toxic effect of emitted Cu ions, without considering influences on the interaction of...

Among the celestial bodies in the Solar System, Mars currently represents the main target for the search for life beyond Earth. However, its surface is constantly exposed to high doses of cosmic rays (CRs) that may pose a threat to any biological system. For this reason, investigations into the limits of resistance of life to space relevant radiati...

Microorganisms are employed to mine economically important elements from rocks, including the rare earth elements (REEs), used in electronic industries and alloy production. We carried out a mining experiment on the International Space Station to test hypotheses on the bioleaching of REEs from basaltic rock in microgravity and simulated Mars and Ea...

Extremophiles are optimal models in experimentally addressing questions about the effects of cosmic radiation on biological systems. The resistance to high charge energy (HZE) particles, and helium (He) ions and iron (Fe) ions (LET at 2.2 and 200 keV/µm, respectively, until 1000 Gy), of spores from two thermophiles, Bacillus horneckiae SBP3 and Bac...

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experimen...

Space exposure experiments from the last 15 years have unexpectedly shown that several terrestrial organisms, including some multi-cellular species, are able to survive in open space without protection. The robustness of bdelloid rotifers suggests that these tiny creatures can possibly be added to the still restricted list of animals that can deal...

One of the primary current astrobiological goals is to understand the limits of microbial resistance to extraterrestrial conditions. Much attention is paid to ionizing radiation, since it can prevent the preservation and spread of life outside the Earth. The aim of this research was to study the impact of accelerated He ions (150 MeV/n, up to 1 kGy...

Carotenoids are promising targets in our quest to search for life on Mars due to their biogenic origin and easy detection by Raman spectroscopy, especially with a 532 nm excitation thanks to resonance effects. Ionizing radiations reaching the surface and subsurface of Mars are however detrimental for the long-term preservation of biomolecules. We s...

Experiments are performed to assess the inactivation of Bacillus subtilis spores using a non-thermal atmospheric-pressure dielectric barrier discharge. The plasma source used in this study is mounted inside a vacuum vessel and operated in controlled gas mixtures. In this context, spore inactivation is measured under varying nitrogen/oxygen and humi...

The filamentous fungus Aspergillus niger is one of the main contaminants of the International Space Station (ISS). It forms highly pigmented, airborne spores that have thick cell walls and low metabolic activity, enabling them to withstand harsh conditions and colonize spacecraft surfaces. Whether A. niger spores are resistant to space radiation, a...

Spores of a variety of bacteria are resistant to common decontamination agents, and many of them are major causes of food spoilage and some serious human diseases, including anthrax caused by spores of Bacillus anthracis . Consequently, there is an ongoing need for efficient methods for spore eradication, in particular methods that have minimal del...

Fungi have been companions of mankind for millennia. Mushrooms inspired our eating culture, and yeasts and filamentous fungi were developed into highly efficient cell factories during the last 100 years to produce many products utilized in different industries worldwide. What more is to come in the next 100 years? We propose here that fungi can bec...

Microorganisms such as archaea, bacteria, viruses, yeast and filamentous fungi (known as “mold”) are an integral part of our human body and our natural environment on Earth. When human space exploration started at around 1961, microbial life has been brought along with astronauts across terrestrial borders and to our space stations Mir (Russian Spa...

Regarding future space exploration missions and long-term exposure experiments, a detailed investigation of all factors present in the outer space environment and their effects on organisms of all life kingdoms is advantageous. Influenced by the multiple factors of outer space, the extremophilic bacterium Deinococcus radiodurans has been long-terml...

Long-term human missions to space require methods for sustaining the health and safety of the crew. Therefore, microbiological monitoring and reduction of contamination is necessary. Microbial biofilms are of special interest because they can cause damage to spaceflight equipment and are difficult to eliminate due to their increased resistance to a...

Gravity is the most consistent physical parameter to which all life has so far been subordinated and has not changed from the beginning of evolution to the present day. Since Apollo 16 the Gram-positive bacterium Bacillus subtilis has been used to study the influence of gravity on vegetative cells, spores and biofilms and still it remains unclear t...

Einleitung: Ob es die Rückkehr zum Mond oder der erste Schritt auf dem Mars ist, den Menschen wird es in Zukunft immer wieder und immer weiter ins Weltall führen. Um die Auswirkungen der im Weltraum herrschenden Umweltbedingungen, wie etwa Schwerelosigkeit, zu simulieren, werden aufwändige terrestrische Studien durchgeführt. Das Deutsche Zentrum fü...

Bacillus subtilis spore inactivation mechanisms under low energy electron beam (LEEB) and high energy electron beam (HEEB) treatment were investigated using seven mutants lacking specific DNA repair mechanisms. The results showed that most of the DNA repair-deficient mutants, including ΔrecA, ΔKu ΔligD, Δexo Δnfo, ΔuvrAB and ΔsbcDC, had reduced res...

The cold, arid, remotely located and perennially ice covered environment of the Antarctic ice sheet is the most hostile place on Earth. It has long been considered an analogue to how life might persist in the frozen landscape of the major Astrobiological targets of our solar system such as Mars or the Jupiter’s ice-covered moon Europa. In the frame...

The exposure to the space radiation environment remains a major limiting factor for human long-duration space missions and permanent presence in space habitats due to its high biological effectiveness and the difficulties to effectively shield the radiation. The next decade in human spaceflight will be characterized by a continuous presence of huma...

In den letzten Jahrzehnten lag der Schwerpunkt der bemannten Raumfahrt auf Missionen im erdnahen Orbit. Die deutsche Raumfahrtmedizin hat sich dabei auf wissenschaftliche Entwicklungen und Anwendungen konzentriert, die Erkenntnisse für das Leben auf der Erde generieren. Zurzeit geschehen diese Missionen ausschließlich auf der Internationalen Raumst...

Aspergillus niger, the model organism for modern biotechnology, is one of the predominant fungus detected aboard the Russian Space Station (Mir) as well as the International Space Station (ISS) [1]. The ability of fungi to colonize a variety of solid and liquid substrates in the stations indoor-closed habitat – e.g. walls, windows, life-support sys...

Microbial contamination of human-tended spacecraft is unavoidable, making the study of microbial growth under space conditions essential for the preservation of astronauts' health and equipment integrity. Previous studies suggested that spaceflight conditions, such as microgravity, cause a range of physiological microbial alterations including incr...

Filamentous fungi such as Aspergillus and Penicillium sp. (also known as “mold”) represent some of the predominant contaminations found onboard the Mir (Russian Space Station) and the International Space Station (ISS). Aspergillus sp. have been found in NASA clean rooms belonging to Johnson Space Center Curation Laboratory as well as in spacecraft...