
Valonia ventricosa - Szpadel
https://en.wikipedia.org/wiki/Valonia_ventricosa
======
twic
I think it's a bit of a cheat to call these things single-celled. They're
really lots of cells where the cells are connected by cytoplasmic bridges.

[https://biology.stackexchange.com/a/28480/3871](https://biology.stackexchange.com/a/28480/3871)

Sure, topologically that's the same, but biology isn't topology. There are
lots of organisms like this:

[https://en.wikipedia.org/wiki/Coenocyte](https://en.wikipedia.org/wiki/Coenocyte)

I don't know this species specifically, but functionally, organisms like this
work much the same as multicellular organisms, with the domain round a nucleus
equipped with protein synthesis machinery and other organelles running mostly
independently, and coordinating with the other ones via chemical signals. It's
just that the signals can move around without having to cross a cell membrane.

EDIT: And if you count this as a single cell, then presumably you'll count a
muscle fibre, which is also many nuclei inside a single cell membrane, in
which case there are larger single cells inside your own body:

[https://www.jneurosci.org/content/25/37/8528](https://www.jneurosci.org/content/25/37/8528)

Well, longer at least.

~~~
EForEndeavour
There's a biological and topological difference between a multinucleate cell
(coenocyte) and an organism made up of distinct cells.

> if you count this as a single cell, then presumably you'll count a muscle
> fibre, which is also many nuclei inside a single cell membrane, in which
> case there are larger single cells inside your own body:

Certainly. Human muscle fibres and nerve axons are single-celled, but they
aren't _organisms_.

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Sniffnoy
Note that this is just _one_ of the largest, not the actual largest. The
actual known largest appears to be this:
[https://en.wikipedia.org/wiki/Syringammina_fragilissima](https://en.wikipedia.org/wiki/Syringammina_fragilissima)

~~~
dang
Ok, we took largestness out of the title.

Or should we just change the URL to the larger one?

~~~
mirimir
Right now, 20% of HN's first-page articles are greyed out. Before today, I
don't recall ever seeing more than one or two. Does this reflect a code
change?

~~~
dang
No. What you're describing sounds like the 'visited' style for links in
titles. Is it possible that you've just clicked on more stories today?

~~~
mirimir
Oh. OK, I am using a different VM. With Firefox and no add-ons. So I guess
that something was blocking 'visited' style.

Edit: Not NoScript.

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fuball63
Reminds me of slime molds. They are large single cell organisms that have
multiple nuclei. A "supercell". I always wanted to keep one as a pet, but I
can never find one despite them being fairly common.

[https://en.wikipedia.org/wiki/Slime_mold](https://en.wikipedia.org/wiki/Slime_mold)

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tdeck
Very cool! As a kid I found these on the beach on vacation in St. Croix. Never
knew what species they were - they turned clear after a night in a glass of
seawater so I couldn't keep them.

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odomojuli
I love seeing submissions like this on the front page. I come for the post-
mortems of severe outages and I stay for the discussion of algae.

~~~
ttyprintk
I'm amazed to see it. Valonia is a pest in reef aquariums. I can't think of
anything less popular, and now it's front-page news.

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pvaldes
Valonia ventricosa bubbles are relatively small, around 4cm. Smaller than many
chicken eggs. Largest viable single cell organism is still the ostrich in its
egg phase.

Unicellular organisms have zero or one nucleus. If they have two or more
nucleus is multicellular

~~~
carterehsmith
>> Unicellular organisms have zero or one nucleus. If they have two or more
nucleus is multicellular

Hmm, is that true? Looks like there are unicellular organisms with multiple
nuclei:

[https://en.wikipedia.org/wiki/Multinucleate](https://en.wikipedia.org/wiki/Multinucleate)

~~~
pvaldes
multiple nuclei means division by mitosis, if a single cell suffer mitosis and
split the nucleus is not a single cell anymore. Are two cells sharing the same
citoplasm and membrane for a while. Cells remaining citoplasmatically
connected with is brothers by a bridge by its entire life aren't uncommon in
some multicellular organisms (is typical of all the kingdom fungi so is pretty
common among life beings in fact).

Valonia vesicles are able to hold several smaller bubbles attached. They
differenciate from the larger bubble by a process similar to gemation and
quickly replace it when is too old or damaged and it bursts. If a bubble
equals a cell in function and looks, an organism able to have rhizoids and
other smaller cells glued to its main cell, is clearly pluricellular.

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wyc
What would this taste like?

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ehfeng
Assuming you pulled it straight from the sea, it'd probably be salty and
slimy.

The internals of cells are mostly water, protein, and DNA, which don't really
taste like anything to our tongues. Most sugars are stored as glycogen, so you
wouldn't get much sweetness. There also wouldn't be much texture, as it's
lacking any sort of bone or shell.

~~~
amfsn
If we leave glycogen in our mouth for seconds/minutes, would the acids in our
mouth decompose it into glucose which would taste sweet? Yes, I have no
knowledge about chemistry.

~~~
tryptophan
Nope. There is no acid in the mouth, and acid doesn't break down carbohydrates
anyways, its all enzymes in the intestine.

Amylase, the thing in the mouth, breaks down starches, like in rice or bread.
Glycogen is different from these though, as it has different linkages, and
can't be broken down by amylase.

~~~
amfsn
Thank you!

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DoreenMichele
_with a diameter that ranges typically from 1 to 4 centimetres (0.4 to 1.6 in)
although it may achieve a diameter of up to 5.1 centimetres (2.0 in) in rarer
cases._

Mind: Blown

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jacobush
What about dinosaur eggs?

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mattigames
> An organism refers to any individual living thing that can react to stimuli,
> reproduce, grow, and maintain homeostasis. It can be a virus, bacterium,
> protist, fungus, plant or an animal.

~~~
pvaldes
This creatures defy definition boundaries. Some act as animals with structures
to run and travel fast, but can photosinthesize also so can fit at the same
time in the old definition of plants. Currently they are neither animals nor
plants. Some fungus walk and climb and some bacterias can act "like a beehive"
with a collective purpose in some phases of its cycle. Bacterias reproduce
when divide, but often its cells remain losely attached in tetrads or chains.

Bird eggs increase its cells by division and sometimes a single egg can
produce two twin animals. Are they reproducting?. Well, in some sense, yes.

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amfsn
What does this look in the inside?

~~~
grenoire
Apparently it consists of a very large vacuole, surrounded by a thin layer of
cytoplasm. Has multiple nuclei and chloroplasts spread around.

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kdmccormick
Are any of the organelles visible to the naked eye?

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grenoire
The cell is a _little_ scaled-up, but the organelles are of normal size.

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amfsn
Heh. So it's like a regular cell but everything inside of it is full of
padding? What is it padded of, water?

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monocasa
No padding, just lots and lots of organelles.

