Enter the world of the xenopus

Every now and then, I get a glorious reminder of just how much the Internet has enriched my life. Fifteen years ago, if I had arrived at a conference center—as I did yesterday for my stint in the Marine Biological Laboratory Science Journalism Fellowship program—and seen a sign in the lobby announcing the presence of a "Xenopus Workshop" I could have, eventually, found out that a Xenopus was a frog frequently used as a model animal in medical research.

Thanks to the Internet, though, I was able to learn the following things in a remarkably short period of time:

Xenopus Fact: Xenopuses (Xenopodes? Xenopi? Freshman Latin was a really long time ago, you guys) were used in one of the earliest reliable pregnancy tests. That's because exposure even a tiny amount of the hormone human chorionic gonadotropin will cause a female Xenopus to lay eggs. Inject a female Xenopus with urine from a human female and, if the Xenopus lays eggs, it means the female human is knocked up.

Xenopus Fact: You know how some lizards can grow a new tail if you cut the old one off? Xenopuses can do that with the lenses of their eyes.

Xenopus Fact: Because Xenopuses are so widely used in laboratories, there's a whole industry of suppliers of Xenopuses and Xenopus accessories. Case in point, the "Xenopus enrichment tube" in the photo above—apparently, they like to have something to hide out in. Also, you can buy synthetic slime to replace your Xenopus' natural protective coating that is often lost through frequent handling.


  1. And you know I am a bad person because I look at the photo and wonder when they are gonna yell “PULL” and launch them.

  2. The Xenopus might be my favorite animal model. It has the sort of alien cuteness that the various lab rats, even the monstrously obese Zucker strain, just can’t quite match.

    1. Plus they are really serene and relaxing to be around.  They had them in labs where I used to work.  I could watch em and just forget my troubles for a while, like sitting by a koi pond.

  3. The plural of Xenopus is Xenopus.

    They were very attractive to scientists because of their large oocytes. It was relatively easy to inject DNA and RNA molecules in these cells and study the function of their respective sequences.

  4. The plural of Xenopus is Xenopus.

    They were very attractive to scientists because of their large oocytes. It was relatively easy to inject DNA and RNA molecules in these cells and study the function of their respective sequences.

    1. Language does not have prescribed rules. You can pluralize anything however you want, and the form that you used is what you meant it to mean. The rules you think you know are merely observations of how, in the past, words have been used — not prescriptions for how one would properly or improperly formulate them.

      1. Oh don’t be ridiculous.  Vacuously, you can pluralize anything however you want, and it will “mean” what you mean it to mean.  The rules — sorry, lemme change that; I think I prefer “the reel” — are merely observationie of how, in the past, wyrd have been used, not prescriptionie.  But if you want to communicate your ideades to other peoplum without confusing theys, it makes sense to pay attention to the community consensus.  And “xenopus” is virtually always the form used by scientister when speaking of these peculiar fröggen in the plural.

        Source: I have been both a linguist and a biologist in my life (and have used xenopussies in the lab).

    2. Xenopus (Gk., xeno=strange, pous=foot)”, which is to say you pluralize it the same way you pluralize octopus — and we’ve been down that road a few times.

      (Xenopodes dammit!)

      There are two Xenopus species popular with lab work, I think it’s laevis and tropicalis, although I remember people being unclear on the species of one of them.  My fuzzy recollection as an IT guy in a bio lab is that one is good for genetic work, but is very small, and the other is a more manageable size for lab work, but is diploid (or tetraploid), and therefore its genome, however redundant, is some order of magnitude larger.

      1. (in reply to everyone concerned about the pacific errors of grammatical ignorami (while drinking expresso))

  5. I’ll never forget watching my high school teacher prepping for the embryology unit.  He’d administered some hormone (quite possibly hCG) to the female to induce ovulation, but he still had to squeeze the eggs out of the female as though she were a pastry tube with webbed feet.  The girls in the class were protesting at the rough treatment he was showing to this poor female frog, and he responded by soliciting some sympathy for the male, pointing to a glass petri dish that held two lumps of tissue, which he proceeded to crush with the end of a glass stir rod, a biologist’s mortar and pestle.  “It’s a lot easier to extract the eggs than it is to extract the sperm.”

  6. “Inject a female Xenopus with urine from a human female and, if the Xenopus lays eggs, it means the female human is knocked up.”

    Granted I’m no scientist, but how exactly does one go about discovering such a thing?

    1.  I’m picturing Tim Robbins’ character in The Hudsucker Proxy as the discoverer, trying to promote his invention: “You know, for kids.”

    2. I imagine by finding checking what hormones might induce eggs in frogs, knowing the same are present in human urine, and then putting the two facts together.

  7. “Xenopus Enrichment Tube” – boingboing is a goldmine of unintentional band names today :)

    1. I’d expect such devices to be manufactured in a facility with the words “the cake is a lie” scrawled on the inside walls of the wire chases and wet-walls.

    2. One of my friends bought a huge, half-million dollar machine that was basically a series of staged Xenopus tanks that would mechanically hatch, raise and maybe even breed them, recycling water and nutrient, etc.  I left the lab before she got it and never saw it, but I like to imagine it as a huge version of one of those glass “biosphere” micro-shrimp things with labeled taps at the bottom: “Egg”, “Tadpole”, “Adult”.

      In reality, I think it actually required a great deal of maintenance.

      1. It’s fitting that the person responsible for getting pregnant women to pee on a frog was named Lancelot

  8. You forgot some more awesome facts about Xenopus :

    Xenopus can live up to 20-25 years, which you may consider when buying it as a pet.

    Xenopus that have just finished metamorphosis are extremely agressive, and will try to kill any other life form living in the same aquarium as them. My sister had two Xenopus albino frogs in an aquarium, and during one night one of the frogs killed nearly all the fish, and also the other frog.

      1. That would have been more convincing if she hadn’t characterized the creature as having “eight legs”.

    1. Right, it means “strange foot” – they have claws, after a fashion, which is a bit strange for a frog.

      That said, a Greekish plural like “xenopodes” seems as pedantic as “xenopi” is mistaken.  “Xenopuses” is perfectly reasonable and I can attest that most scientists just use a zero plural, saying e.g. “The xenopus are ready for your experiment.”  (Or just “The frogs.”) 

      I prefer “Xenopussies” myself, with a nod to their slightly cat-like nature.

    2. This is an annoying misnomer. They are derived from Greek, but for genera, the grammatical form is always Latin. The traditional plurals are -podes as a Latin third declension.

  9. I have one, his (or her) name is, at times, Froggly, Ser Frogbert, Frogston Sinclair Lewis, or Frog. Also Frogster.

    Fun fact: my Xenopus’ breath smells like Xenopus food.

  10. I hear Japanese people are xenophobic. You would think they’d like a frog as cute as that. ;)

  11. Evidently I misunderstood what Xenopus accessories meant, because I want to  know what  it would take to engineer some of these to have chromatophores that  appear as Louis Vuitton logos.

  12.  Xenopus thought it was ever so clever and cool at survival what with it’s evolutionary regenerative abilities and all that.

    Then it became useful.

    To Humans. :(

  13. When I was about 13, my biology teacher managed to persuade a pair of Xenopus to breed (probably by the squeezing and mashing operation described above). Suddenly, he had tankfuls of Xenopus toadlets that he didn’t know what to do with.

    He gave a pair to every kid who wanted them. I named mine Claudia and Claudius (because the other name for Xenopus is the African Clawed Frog). Claudius disappeared fairly early on, possibly eaten by Claudia, but Claudia lived on in a fishtank on top of the fridge in my parents’ house, hand fed on an intermittent diet of earthworms by my father. For the next twenty-five years.

    As @Teknad said, these little guys live for a long, long time …

  14. I love my Xenopus, Fireball. Bought him as a tadpole through the mail for my son’s fifth birthday. Nine years later still going strong. Guests love watching him eat frozen bloodworm cubes in a very Cookie Monster sort of way.

  15. These are also the critters that wreaked havoc on that lily pond in Golden Gate Park. First, they ate everything in the pond, including the turtles. Then they proved to be very hardy and impossible to remove/exterminate. The pond is also infested with some invasive weed, but they can’t kill the weed unless they fix the pond, and they can’t fix the pond because they’re afraid if they drain it, the frogs will spread.

    The original headlines were kind of memorable: FLESH EATING FROGS TERRORIZE GOLDEN GATE PARK and the like.

    1. There’s also a colony of X. laevis in South Wales: http://www.botany.uwc.ac.za/presents/focuson/frogs/feral.htm

      Hardy little beasts …

  16. I believe they used to clone genes in bacteria to create a lot of mRNA, then inject the RNA into the egg with some radioactive amino acids, which would create the protein of interest (radioactive) so you could study things like how it had been processed post-translation. It’s not always obvious from the gene where it starts and ends or what the protein’s molecular weight or solubility would be.  But if you have your protein of interest labeled with isotope, you can discern things like that even without purifying it. 

  17. When I clicked “xenopus accessories”, I was expecting little xenopus hats and monocles.  I have been left utterly disappointed!

  18. More Xenopus facts :-)
    – As fully aquatic species, they have a series of unique characteristics: no eardrums, no eyelids, and the adults retain the lateral line system (“distance touch”) that usually disappears during metamorphosis in other frogs.

    – They also lack a tongue, so they use their throat as a pump to suck food in.

    – They have horny claws in some of their digits (thus their “strange foot” name)

    They are indeed alien-y cute, but I don’t like the albino individuals quite so much.

  19. God, yeah, that’s really interesting that researchers are using these living breathing creatures that are fully capable of experiencing terror, pain and death to further pregnancy piss test science. “Apparently they like to have something to hide out in…”. No.shit.

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