Thread by @biol346

LET'S GET READY TO RUMBLE!
It's Round One of March Microbe Madness, and our 32 fantastic yet tiny competitors are ready to fight it out for microbial glory.

But first, a quick recap of the rules. Each pair of mighty microbes will face off in one of four randomly selected environments: soil, ocean surface, freshwater lake, and the human gut.

The winner is selected by BIOL346 votes UNLESS they would not survive the environment and their competitor would. This is how upsets can happen!

BIOL346, you've submitted your brackets. It's no surprise that last year's runner-up is a strong contender, with the most students choosing Tardigrade as their champion!

But Team Tardigrade is not assured of victory! It was the #1 choice last year too, but Team Cyanobacterium got out the vote.
Other teams are emerging, with Team E. coli and Team Deinococcus representing!

A handful of other organisms are also chosen champions, including the literal home-grown favorite, Lactobacillus, whom many of you likely have in the sauerkraut on your counters.

Let's get started! For the inaugural 2022 March Microbe Madness battle, we start with the BACTERIA DIVISION, with Dehalococcoides mccartyii facing off against Escherichia coli K12 in SOIL.

Dehalococcoides mccartyii is a rare bioremediation success story - one of very few species that can completely degrade chlorinated solvents to the non-toxic ethene. They are typically found in subsurface aquifers and are HIGHLY oxygen sensitive.

Prior work had visualized them as flattened cocci, somewhat like a red blood cell. Work published January of this year using cryo-electron tomography showed this shape was an artifact - the cells are more rounded. pubmed.ncbi.nlm.nih.gov/34788060/
How it startedHow it's going

E. coli are frequent denizens of soil, including pathogenic strains able to join plant rhizosphere communities, a potential route for food-borne illnesses. purdue.edu/newsroom/resea….

Dehalococcoides are not as comfortable in soil as E. coli. Dehalococcoides might find a micro-environment without any oxygen to persist in, but with the ability to thrive AND a whopping 96% of the vote, E. COLI ADVANCES.

Next up in the BACTERIA DIVISION is Lactobacillus versus Geobacter, the new competitor to the bracket, battling in the HUMAN GUT.
Lactobacillus is no stranger to the human gut, as one of the most common organisms cultivated from the stomach, intestine, and feces.

However, as we know, cultivability does not always represent underlying communities well. Lactobacillus usually represents <1% of any human gut sample, and is hypothesized to mostly be transient (allocthonous), coming in on fermented foods like sauerkraut! ncbi.nlm.nih.gov/pmc/articles/P…

Geobacter is a hardy microorganism famous for growing nanowires to harvest electrons from metals millimeters or even centimeters away! genengnews.com/news/microbial…

Super cool, but there's not much metal in the human gut...

However, there ARE electrogenic organisms in the gut, which might be options to power tiny batteries inside the body. pubs.acs.org/doi/10.1021/ac…
We're a long way away from that reality, but Geobacter has been seen in gut samples, and the anaerobic environment would suit it.

Both competitors are found in the human gut, so we turn to the voters to decide. With 68% of the vote, LACTOBACILLUS ADVANCES. Team Lactobacillus can breathe easier.. for now!

Next up in the BACTERIAL DIVISION are Rhizobia versus Pseudomonas, who will be battling it out in SOIL.
Both of these organisms are very comfortable in this environment.

Rhizobia are plant growth-promoting bacteria that live inside nodules of plant roots. They fix nitrogen for the plant, and receive protection and lots of tasty exudates in return. This is one of the best-described microbe-plant interactions.
pubmed.ncbi.nlm.nih.gov/36624/

Pseudomonas are ubiquitous in soils and surface waters. They were first described by Polish-born German microbiologist Walter Migula in 1894: "Cells with polar organs of motility. Formation of spores occurs in some species, but it is rare." ncbi.nlm.nih.gov/pmc/articles/P….

Neither organism is going to yield to the environment, but one was the clear class favorite - with 84% of the vote, PSEUDOMONAS ADVANCES

In the final battle for the BACTERIAL DIVISION, we have Commamox Nitrospira facing off against Patescibacteria in the HUMAN GUT.
Neither of these competitors are commonly found in this environment - can they survive?

Commamox Nitrospira are one of the most exciting discoveries of the past decade in microbiology. Connection of ammonia oxidation and nitrite oxidation to form complete nitrification in a single organism was long hypothesized - and then discovered!
natureasia.com/en/nature/hot-…

Commamox as a process is most often found in slow moving, low nutrient systems - the exact opposite of the human gut! However, Nitrospira organisms are frequently found in the gut, so it's likely Commamox Nitrospira would survive.

They might even thrive... if their host does too. Nitrospira were found in higher abundance in mice who were diabetes resistant following a high-fat diet. gut.bmj.com/content/61/4/5…

Patescibacteria is a phylum-level radiation of tiny cells with even tinier genomes and reduced metabolisms. They are hypothesized to be symbionts or parasites on larger bacteria, or possibly just very good scavengers.

As for the gut, Patescibacteria have been seen in human samples, including from the small intestine, though often at very low abundance. Their reduced metabolism made them difficult to support - and with 76% of the vote, COMMAMOX NITROSPIRA ADVANCES.

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