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Microbes Might Be Key to a Mars Mission

Engineered yeast could turn waste into food, plastics and other essentials

By Mark Blenner on January 14, 2019

Image Credit: NASA, Clouds AO and SEArch Wikimedia

Blenner, M. (2019, January). Microbes Might be Key to a Mars Mission.  Scientific American.  Retrieved from  https://blogs.scientificamerican.com/

Summary:

The author describes the work of his team as they engineer modified versions of the yeast  Yarrowia liplytica.  Dr. Blenner suggests strains of the modified yeast could survive on waste products from astronauts while creating materials to facilitate repairs and improve astronaut health. Genes “borrowed” from other organisms could allow the modified yeast to generate useful products. For example, these products could be used as the building blocks for 3-D printed parts or for adhesives used for repairs. One strain of the modified yeast uses genes “cut and pasted” from plants and algae to produce eicosapentaenoic acid (EPA). This valuable Omega-3 fatty acid is a neutraceutical known to help prevent bone density loss in astronauts.

Connections:

In lecture, we discussed yeast as a model species. This organism is often mistaken for a prokaryote by new biology students, perhaps because it is small and single-celled. These fungi have a membrane-bound nucleus, however, and are thus eukaryotes. Use of yeast strains as model species predates work begun by Dr. Blenner in 2012.

In lecture we also touched on synthetic biology, and its similarity to traditional genetic engineering. In genetic engineering, genes known to code for products resulting in desired traits are “added to” an organism’s genome. The desired traits referred to in this article are: 1) the consumption of astronaut waste products and 2) the production of products useful to astronauts during space travel.

Finally, a Microbes in the News article posted by @kcallegari discusses the hardy nature of microbes found in the International Space Station (ISS). I think the evidence of mutations in the bacteria found in the ISS may have applications in the engineering of the yeast strains Dr. Blenner’s team is working with. I think it would be interesting to consider what mutations are already present in the “space generations” of bacteria, and what might happen if similar mutations occur in modified fungi.

Critical Analysis:

This blog was written in a conversational, non-jargon language which made the main points easy for anyone to understand.   Dr. Blenner referenced a recent scientific publication, and gave a one-sentence summary of those findings (Brabender 2018). He then connected this to his current research, which validated the need for this avenue of investigation. This was effective scientific communication because raising awareness of potential benefits to this area of study is the best way to bolster interest and thus funding for further research.

I felt there was some implication that the products from the modified yeast strains were sure to be useful to astronauts, which isn’t supported by the findings he presented in this article. However, I can understand that determining how to harvest and utilize those products and proving that the processes would be worth the time and tools it might take wasn’t the purview of the current study. This may be the next stage of study for his team, or may be the task for another team of scientists. Perhaps acknowledging the limitations of the current study may have made the need for future supporting studies seem less glossed-over.

I thought citing his background in studies of synthetic biology and yeast helped to authenticate Dr. Blenner’s article, as did his bio, which notes the funding source for the current research. In all; the article identified a real-world need, referenced published scientific literature, explained how the current study aimed to address the real-world need, and suggested potential benefits of further study. It was an effective use of the blog forum to garner awareness and potential support both for his team’s current research and for future studies.

Question:

I understand scientists use model species because these species have characteristics universal enough to apply to other species across the tree of life. In the studies this article describes, the DNA regions of interest being transferred are from simple organism to simple organism. The regions cut and pasted into other organisms’ genomes can include one gene or several genes, as well as parts of the non-coding regions surrounding those genes. This may have relatively straightforward results in single celled organisms. Yet in multi-celled organisms, there are innumerable inter-systemic interactions in the micro-chemistry unique to each species. For example, a single neurotransmitter can affect both brain chemistry and gut processes (Li 2004). Is it productive and ethical to experiment with inserting regions of interest into more complex species before the biochemistry of inter-dependent bio-systems are fully mapped out?

References:

Brabender, M., Hussain, M.S., Rodriguez, G. et al. Urea and urine are a viable and cost-effective nitrogen source for  Yarrowia lipolytica  biomass and lipid accumulation. Applied Microbiol Biotechnology (2018) 102: 2313. doi.org/10.1007/s00253-018-8769-z.

Li, Z.S.,  T. D. Pham,  H. Tamir,  J. J. Chen  and  M. D. Gershon.  Enteric Dopaminergic Neurons: Definition, Developmental Lineage, and Effects of Extrinsic Denervation.  Journal of Neuroscience  (2004)  24:  1330-1339.  doi.org/10.1523/JNEUROSCI.3982-03.2004.