Bacteria Offer New Possibilities for Radiation Protection

Bacteria ≠ Fungi

Bacteria are single cell prokaryotes (they lack nuclei and other organelles). Fungi are multicellular eukaryotes with nuclei and organelles.

Interesting article.

I'm surprised the article does not mention what I believe will be the more immediate use of this fungus. Since this fungus spreads towards higher radiation areas it can be used as an area radiation indicator. I realize this fungus may not be easy to detect as it exists but adding the bioluminescence gene to this fungus (a process that has already been performed on many other species) will be far easier than transferring the radiation-resistant trait to an ailing patient so they can get more radiation treatment. Wait, what if the tissue the radiation is trying to kill also becomes radiation-resistant?

A fungus that can not only survive radiation (like a cockroach), but thrive in it - and convert the radiation into other forms of energy sounds like a great thing for remediation like Fukushima.

My only concern is "The law of unintended consequences". How do you kill a fungus that can do that after the remediation is done? And please don't say antifungal cream.

Ionizing radiation causes damage by removing electrons from molecules. Melanin has the ability to repair this damage and to receive new electrons to replace those removed by Gamma-Radiation.

This article provides a pretty good explanation...

"Research at the U.S. Department of Energy's Savannah River National Laboratory, in collaboration with the Albert Einstein College of Medicine, has provided insights into the electrochemical mechanism that gives the complex polymer known as melanin its long-term radioprotective properties, with a goal of using that knowledge to develop materials that mimic those natural properties.

A recent article in the journal Bioelectrochemistry relates how the researchers established that ionizing radiation interacts with melanin to alter its oxidation-reduction potential, resulting in electric current production.

Radiation causes damage by stripping away electrons from its target. "Over time, as melanin is bombarded with radiation and electrons are knocked away, you would expect to see the melanin become oxidized, or bleached out, and lose its ability to provide protection," said Dr. Charles Turick, Science Fellow with SRNL, "but that's not what we're seeing. Instead, the melanin continuously restores itself."

The team's research took them one step closer to understanding that self-restoration mechanism. They demonstrated that melanin can receive electrons, countering the oxidizing effects of the gamma radiation. The work showed, for the first time, that constant exposure of melanin to gamma radiation results in electric current production.

Mimicking that ability would be useful, for example, in the space industry, where satellites and other equipment are exposed to high levels of radiation for long spans of time. "Looking at materials, a constantly gamma radiation-oxidized electrode consisting in part of melanin would continuously accept electrons, thereby resulting in a current response," Turick said. "If we could understand how that works, we could keep that equipment working for a very long time." "

https://www.sciencedaily.com/releases/2011/08/110823165352.htm

http://einstein.yu.edu/uploadedFiles/casadevall/new_website/paper/2011/Turick_Ekechukwu_11.pdf

The things 'we' learn.

It will certainly be interesting to see where this all could lead.

This may put a new light on it. Fungi evolved long ago when the earth had much higher background radiation. These melanized fungi have been barely holding on, and the places like the inside of the Chernobyl reactor are more like what they like.

"Life emerged on Earth at a time when there was much higher background radiation and early life forms must have considerable radiation resistance. Although current background radiation levels are much lower than on the early Earth, earthly life still exists in a field of radiation. For example, 90% of the annual radiation dose for a person living in the US comes from natural sources such as cosmic radiation and radioactive rocks (1). However, there is considerable evidence that fungi respond to radiation in a manner that may differ from other life forms. Large quantities of highly melanized fungal spores have been found in early Cretaceous period deposits when many species of animals and plants died out. This period coincides with Earth’s crossing the “magnetic zero” resulting in the loss of its “shield” against cosmic radiation (2)."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2677413/

So as opposed to the implied radiation induced mutation to liking higher radiation this fungi was "lurking in the shadows" all along. I like the idea. I still like my bioluminescence proposal.

Another factor could be that radiation gets rid of the competition. There is a parallel in antibiotic-resistant bacteria, where antibiotics, which kill 99.9% (the nice guys), leave room for the 0.1% (nasties) to fill the void.

Space probes that we have sent to other planets are routinely sterilized. I'm wondering what is still alive and thriving after this process.

Somebody's working on that.

https://www.jmirs.org/article/S1939-8654(19)30069-4/abstract

I wouldn't be too optimistic about sunblock. "With reference to the study of the medical effects of nuclear war, the field of mycology is arguably the most neglected subdiscipline of microbiology.....Melanin contributes to the virulence of fungal pathogens.....Approximately 70 genera of melanized fungi are associated with human and animal disease."

https://academic.oup.com/milmed/article/179/11/1181/4159930

Apparently melanin's tendency/capacity to bind things is a reason for the virulence, although in plant pathogens it also strengthens the parts that penetrate the leaf to do the dirty work.

Some of the research on cooler applications or possible applications are discussed on page 17-18 here, including the medical applications and bioremediation. And electric current production! I could see that on the hull of your spaceship.

Synthesis and assembly of fungal melanin
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4318813/