Mutualism of the Month: You're eating for 100 trillion, cross-feeding microbes and their humans

Mutualism of the Month: You're eating for 100 trillion, cross-feeding microbes and their humans

You may have heard there’s more bacterial cells inside you than human cells; it’s true. There’s about 10 times as many bacterial cells (~100 trillion) compared to human cells (~10 trillion). It’s estimated that there may be up to 1,000 different species of bacteria living in the human gut! Gut microbiota (not flora, flora are plants) make up to 3% of your total body weight. Find out how you work together with your gut bacteria in April's Mutualism of the Month!

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Mutualism of the Month: Tetrodotoxin-producing bacteria and their many hosts

Mutualism of the Month: Tetrodotoxin-producing bacteria and their many hosts

This month’s mutualism is between tetrodotoxin-producing bacteria and their many hosts.

Until recently, the origin of the tetrodotoxin (TTX) in pufferfish was unknown. TTX was first isolated by chemists from the ovaries of pufferfish in 1950. It was thought to be a toxin found exclusively within pufferfish (hence its naming after the pufferfish family Tetraodontidae), until it was found in the California newt Taricha torosa. After its discovery in newts, TTX was rapidly isolated from a diversity of animal species completely unrelated to each other, including several frogs, an octopus, several marine snails, a crab, and a starfish. This raised an interesting question: did all these animals evolve the ability to produce tetrodotoxin separately or is there some common factor?

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Mutualism of the Month: Hawai‘ian bobtail squid

Mutualism of the Month: Hawai‘ian bobtail squid

This month’s mutualism is the Hawai‘ian bobtail squid Euprymna scolopes and its bioluminescent bacteria Aliivibrio fischeri.

The Hawai‘ian bobtail is a small (1.5”), nocturnal squid endemic to the Hawai‘ian Islands.  Vibrio spp. are gram-negative facultative anaerobes (they don’t need oxygen) typically found in seawater, some of which can cause foodborne illnesses related to consuming shellfish.

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