His 37+ years of research span a wide range of topics, including marine, food, and environmental microbiology. He directs several research and development tasks for JPL’s Mars Program Office, which enables the cleaning, sterilization, and validation of spacecraft components.
What led to your interest in this area of research?
While directing several NASA projects on the microbial monitoring of extreme environments, including spacecraft and associated surfaces, I became interested in the microbiome of closed habitats like the space station or its Earth analogues.
By ‘microbiome’ I mean the ecosystem of microorganisms in a particular environment. We are investigating how to transfer molecule-monitoring technologies developed at NASA/JPL to other industries.
For example, they could perhaps be used by commercial airlines for monitoring cabin air. We are also working with a medical company to apply this technology to the processing of tissue and organs for transplant, so that pathogens that are problematic for humans can be detected.
What did you set out to investigate and why?
The safety and health of spaceflight crew members are of the highest importance for current and future missions. Individuals living and working in such environments are often susceptible to health issues associated with microorganisms.
By exploring the microbial diversity associated with unusual human-built environments such as the space station, we can further contribute to indoor microbiome research.
Moreover, the microbial ecology of the space station remains largely unknown, as study efforts have been mostly focused on microbiological surveillance using cultivation procedures.
The National Research Council recommended the use of state-of-the-art molecular biology techniques to develop better microbial monitoring of future closed habitats and response systems against potential biohazards originating from microbiological sources, using the space station as a test bed.
By exploring the microbial diversity associated with unusual human-built environments such as the space station, we can further contribute to indoor microbiome research. This will benefit the development of spaceflight applications as well as basic and applied research on Earth.
Could you briefly outline the main findings from your study?
The results of this study provide strong evidence that specific human skin-associated microorganisms make a substantial contribution to the space station microbiome.
In this respect, the space station microbiome is significantly loaded with Corynebacterium and Propionibacterium (Actinobacteria) but not Staphylococcus (Firmicutes) species, as seen in culture-based analyses in terms of viable and total bacterial community composition.
The present results also demonstrate the value of viable cell studies. In particular, these studies provide insight to the viable population size at any sampling site. This information can be used to identify sites that should be avoided or targeted for more stringent cleaning conditions.
Finally, the results obtained in this study will allow comparisons with other human-built sites and facilitate future improvements on the space station that will promote astronaut health.
What does this mean for future research?
Rapidly recognizing the presence of viable microbial pathogens in a closed system is required for NASA, and our technical approach would help the agency measure microbial pathogens and develop a ‘quantitative microbial reduction assessment’ tool for predicting problem and mitigating with appropriate countermeasures.
Sequencing of space station samples can answer questions about the abundance and diversity of the microorganisms. However, differentiating viable and yet-to-be-cultivable microbial populations requires sample-processing technology.
The novel sample-processing approach implemented in this study allowed for a more accurate approximation of the viable microbial community in terms of richness as well as abundance.
The novel sample-processing approach implemented in this study allowed for a more accurate approximation of the viable microbial community in terms of richness as well as abundance. Due to the technically rigorous methods required for culturing many microorganisms, characterization of human-associated microbial populations in the space station environment remains a significant challenge.
However, it is important to monitor the presence of any opportunistic pathogenic microorganisms. As long-duration human missions are planned in the future, detection of human pathogens and possible mitigation practices must be developed.
In addition, if we better understand the space station microbiome, we could facilitate the necessary maintenance of this closed habitat and help prevent microorganisms from degrading some of its components.
How has research advanced during your career? Has this helped with getting these results?
The bioinformatics databases that our team generates are extremely useful in the development of biosensors. Further, these models and databases can be applied to what is known about the spacecraft surfaces and enclosed habitats so that we can estimate contamination, as well as develop countermeasures (advance cleaning and sterilization technologies) to control the problematic microbial species.
Specifically, my group’s research into the study of clean room environments using state-of-the art molecular analysis, coupled with nucleic acid and protein-based microarray, will allow accurate interpretation of data and implementation of planetary protection policies of current missions. Our research will also help set standards for future life-detection missions.
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