7th joint conference "Joint Microbiology & Infection Conference 2024" of the DGHM and VAAM

Chair

Abstract: Experiments conducted in space are a rarity, making the opportunity to perform one on the International Space Station (ISS) exceptionally thrilling. However, apart from having a significant scientific query to address and a hypothesis that can only be tested in space, there are other essential elements required for success - dedication, patience, and resilience. The experiment known as LUX-In-Space serves as an exemplary case study, highlighting the various stages involved in its preparation, the timeline, and its current progress.
In space, all organisms are exposed to and affected by space radiation and microgravity. Radiation and microgravity were identified as two of the five most important hazards for manned spaceflight. Therefore, the knowledge of biological space radiation effects as well as the impact of microgravity on enzymatic repair processes is mandatory for risk assessment, especially in view of long duration missions to Mars or permanently inhabited bases on the Moon. 
The repair kinetics of radiation induced DNA damages will be investigated with the SOS-Lux Test.  Bacteria serve as model organisms. They possess the same type of nucleotide excision repair as all other living organisms including humans. Salmonella enterica subsp. enterica cells are transformed with the pBR322-derived plasmid pPLS-1, carrying the promoterless lux operon of Photobacterium leiognathi as the reporter element controlled by a DNA damage-dependent SOS promoter as sensor element. In response to exposure to radiation the SOS promoter is activated. Due to the genetic modification, the connected so-called lux genes are expressed, resulting in the emission of measurable bioluminescence proportional to the applied dose of radiation. The DNA repair kinetics are followed by bioluminescence and optical density measurements.
LUX-in-Space is the first space experiment where the whole series of events from DNA damage induction in metabolically active cells to the different steps of enzymatic repair will take place in real microgravity and the repair kinetics will be monitored in situ by optical measurements. The effects of microgravity will be clearly separated from other spaceflight factors by comparison with parallel samples on an onboard 1g centrifuge in the Biolab facility on the ISS and in a parallel ground control experiment with identical samples in flight-identical hardware. 

LUX-in-Space - the long and stony way to Low Earth Orbit

Invited Speaker

Invited Talk

Abstract: Introduction
Microbial examination of flight hardware and cleanrooms is a major focus of planetary protection activities to control bioburden and to analyze the complexity of the cleanroom microbiome.
Enriched isolates from samples collected during various missions, including ExoMars and JUICE, have been identified and deposited at the DSMZ to establish a special strain collection of bacterial species that can survive and adapt under extreme conditions. Cultures originally obtained from the International Space Station (ISS) or isolated within the Mars Analogues for Space Exploration project (MASE) complement the collection with additional strains.
The collection was founded by the European Space Agency (ESA) and is publicly accessible via the online strain catalog at the DSMZ and is also integrated into the BacDive database.
Objective
ESA has implemented the public culture collection to facilitate the distribution of bacterial isolates to the scientific community. This allows researchers to study specific properties of these microbes to gain insights into the survival and adaptation mechanisms in extreme environments.
Current status
Spacecraft are built in particle-controlled clean rooms. Particles can affect the function of spacecraft instruments, and for missions under planetary protection restrictions, biological contamination must be limited as much as possible. A clean room is an extreme environment with constant control of humidity and temperature, air filtering, and surface disinfection. Bioburden and diversity studies have been performed for several missions (Smart-1, Rosetta, Herschel, ExoMars and Juice) in various European clean rooms to validate biological contamination control and reduction procedures.
Swab and wipe samples were collected from clean room facilities and directly from spacecraft surfaces by our collaborators from DLR in Cologne and the University of Graz. Most isolates enriched from these samples have been identified and freeze dried at DSMZ for long-term storage. The collection currently contains about 900 isolates, with the predominant species belonging to the endospore forming genera Bacillus, Paenibacillus, Peribacillus and Priestia. Other representative species are from the genera Acinetobacter, Stenotrophomonas, Micrococcus, Kocuria and Staphylococccus. Selected isolates are now being genome sequenced to gain further insights and to refine its phylogenetic assignment.

Planetary protection and ESA’s bacterial strain collection

Abstract: Introduction: The search for life on Mars involves understanding the habitability of its surface and near subsurface, particularly in relation to the presence of salts and their solutions, such as perchlorates (ClO4-), which were detected on the Red Planet but are rare on Earth. Studies of our research group aim to investigate the microbiological responses to Martian-relevant salts, focusing on their tolerances and stress reactions.
Goals: The primary objectives included determining the salt tolerances of various halophilic and halotolerant microorganisms, assessing their survivability under Mars-like conditions, and analyzing their stress responses.
Materials & Methods: Microorganisms, including model species and environmental isolates, were subjected to varying concentrations of sodium perchlorate (NaClO4) and other salts to assess their tolerances. Mars-like environmental conditions were simulated in a chamber, and survival rates in Martian regolith mixed with different salts were measured. Salt stress responses were analyzed using microscopic, proteomic, and metabolomic techniques.
Results: Most halotolerant organisms exhibited higher NaClO4 tolerances than obligatory halophiles, suggesting their adaptability to habitat-untypical salts. The halotolerant yeast Debaryomyces hansenii demonstrated the highest tolerance, leading to further investigations. Chlorates (ClO3-) were tolerated in significantly higher concentrations than perchlorates, suggesting an increased habitability potential for chlorate-rich areas on Mars. Proteomic analyses revealed perchlorate-specific stress responses, particularly in D. hansenii, indicating chaotropic stress as a significant factor.
Summary: Experiments in Mars-simulated conditions showed that Martian subsurface may offer a more hospitable environment than the surface, with chlorates enhancing habitability over perchlorates. Microbial stress responses to perchlorate, analyzed through morphological, proteomic, and metabolomic approaches, highlighted species-specific reactions, emphasizing the necessity of understanding adaptations to Martian conditions for future astrobiological research.


Unraveling Martian Microbial Survival Strategies: Insights from Salts, Stress Responses, and Habitability

Abstract: Biofilms are a significant challenge in environments such as hospitals and industrial facilities, but also in space environments. Microbial induced corrosion due to biofilm formation, biofouling and clogging of pipes are serious threats to the integrity of spacecraft. In addition, biofilms can harbor and act as reservoirs for opportunistic pathogenic microorganisms, which could pose a threat to astronaut health, especially since astronauts exhibit a compromised immune system during spaceflight. Antimicrobial surfaces are one of many mitigation strategies against microbial biofilm formation. Copper has been known for its antimicrobial properties since ancient times, and additional surface modification using Direct Laser Interference Patterning (DLIP) has been shown to increase antibacterial efficacy. However, the interplay between cells, their environment and surfaces under space conditions requires further investigation, as fluid dynamics, mass transport and sedimentation are different in microgravity. The BIOFILMS experiment was selected by the European Space Agency (ESA) to test antimicrobial copper-containing surfaces against bacterial adhesion and biofilm under reduced gravity conditions on the International Space Station (ISS). The BIOFILMS experiment included three flights to the ISS from August 2021 to March 2023, during which the bacterial model organisms Staphylococcus capitis, Cupriavidus metallidurans, and Acinetobacter radioresistens were incubated on various surfaces inside specially designed hardware to ensure a controlled environment. Preliminary results show no negative effect of reduced gravity on the antimicrobial efficacy of copper and no clear effect of gravity conditions on adhesion and biofilm formation on the reference stainless steel surfaces. The final results of the project will provide valuable insights into selecting suitable surfaces and functionalization techniques to reduce biofilm formation, increase safety, and improve the sustainability of space travel.

Symposium
Space Research on Earth

Appointment

Chair

Programme

SymposiumSpace Research on Earth

Appointment

Chair

Programme

Symposium
Space Research on Earth