The Earth Story

Biofilms

You wake up in the morning with “dragon breath” and you just can’t wait to brush that yucky scum off of your teeth. Obviously, you don’t get all of it because every six months, you still have to sit in the dentist’s chair while the dental hygienist uses what feels like a pickaxe to chip away at your teeth to remove plaque buildup. There’s no denying that as much as you might work to prevent plaque, it’s hard to get rid of.

You go to the farmers market on Saturday morning and along with all of the fresh, locally sourced produce, someone is selling a fermented tea mixture known as kombucha. Advertised as an immune system stimulant and as a cure for a variety of illnesses, kombucha is a culture of bacteria and yeast that form a floating film on the surface of the liquid. In 2014, the European Space Agency attached a container named Expose R2 to the outside of the International Space Station for an 18-month trip around the Earth. Among the 758 samples of organic materials in the container is kombucha.

What do going to the dentist, a popular hipster beverage, and outer space have in common?

Biofilms.

When we visualize bacteria and other microbes, it’s usually in the form of the single pill-shaped organisms with squiggly appendages depicted in biology textbooks. And there are certainly a lot of those solitary microorganisms in, on, and around us. However, many species of microbes don’t like the insecurity of living alone. They best survive when attached to one another and to the surface on which they live. These organisms can be found joined to others of the same species in chains or clumps, but a large number of microbes live in commensal relationships with other species of bacteria, yeasts, algae, and protists, often forming large, slimy mats. So, in the dark, damp environments that many microbes prefer, they secrete a matrix of polymers that glue them to the surface and to one another. The film on top of kombucha and yes the morning scuz on your teeth are both biofilms. According to the CDC (Center for Disease Control), cystic fibrosis (a lung disease), native valve endocarditis (in the heart), otitis media (the most common type of ear infection), periodontitis (gum disease), and chronic prostatitis (inflammation of the prostate glands) all appear to be caused by biofilm-associated microorganisms.

This slimy coating provides a great degree of protection for its microscopic inhabitants. Medically, infections of biofilm-producing organisms are hard to treat, often becoming chronic illnesses due to extreme antibiotic resistance granted by the polymeric matrix.

Since some terrestrial microorganisms are able to shield themselves from extreme conditions like high acidity, heat (as in the attached image from Yellowstone National Park), salinity, etc., by secreting and surrounding themselves with a protective polymeric matrix, scientists designed the experiments contained in Expose R2 in order to see if these EPS (extracellular polymeric substances) could impart similar protection from the harsh conditions found in space or on other planets, such as Mars.

The results of the experiments contained by Expose R2 may give scientists greater insights into what sort of conditions extraterrestrial organisms might be found in, how organisms respond to prolonged exposure to U.V. radiation, ways to treat antibiotic resistant bacterial infections, and how life forms may have survived the harsh conditions that existed on early Earth. That’s a lot to learn from scum.

CW

Image by the author (hot spring in Yellowstone National Park, about 1.5 m X 1.0 m (4 ft. X 3.5 ft.)

Sources

http://bit.ly/1QefhYF

http://bit.ly/1QefjQu

http://bit.ly/1Nt6D7W

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2732559/

http://www.ncbi.nlm.nih.gov/pubmed/23635385

http://wwwnc.cdc.gov/eid/article/8/9/02-0063_article

http://bit.ly/1MdA9Ku

http://www.nps.gov/features/yell/tours/fountainpaint/bacteria.htm

http://www.toddneff.com/articles/HealthBio/Yellowstone.html

https://en.wikipedia.org/wiki/Biofilm