responses to the largest cell on Earth question

Kevin Shreder kshreder at znet.com
Thu Feb 20 11:11:11 EST 1997


I recently posted a question inquiring about what the largest cell on Earth was and I got 
several interesting responses.  I suppose there was such variety because I was vague - what 
exactly does "large" mean?  The heaviest, the longest, the most voluminous?  In any sense, 
here are just some of the many responses I got:


The largest cell on earth would be an egg of one of the larger
birds eg emu, ostrich, casuari (sp?), no other type of cell has the needs
of storage that an egg does, and only a large animal can produce eggs the
size of an emu egg.  Perhaps a news group on birds would be more
informative?
        Plantwise it would probably be a giant algae, the name escapes me
for the moment, but there is an algae used in experiments on plant
physiology becaue of it's large size, principly for rates of cytoplasmic
streaming.  Now I have it - there are two algae "Chara" and "Nitella"
        The longest cell would be a nerve cell of the giant squid.
        The largest surfaces area would, I guess, belong to a 'skin' cell,
but I have no idea which species has it.

I hope this is of some use to you.

WT                



Depends what you are after - the largest cell in a multicellular organism or
the largest cell of any type!

For the latter, the alga Valonia would be somewhere near the mark but I'm
sure there are bigger - memory is a bit deficient after 7 years of
retirement but have a look in a good Plant Physiology text since early ion
and nutrient exchange work used them for hypodermic extraction of internal
fluids in the sorts of quantities required in early days!

The 1969(??!!) edition of Salisbury & Ross "Plant Physiology" gives Chara,
Halicystis and Nitella spp as also being large celled but the Nitellas I
used to handle were not as large as Valonia (cm rather than mm!!). Later
editions were more process orientated and fascinating byways such as this
on size seemed to have been lost.

Best success but I hope you can authenticate a few measurements!!!

I may be able to give one example of larger cells than those you listed: A marine diatom 
which is unicellular plant leaving in ocean, its name is Ethmodiscus rex. It length is about 
0.9 mm, and width about 0.5
mm.

SL


Further to my earlier response - having been a botanist and your query being
in a plant Newsgroup I never gave a thought to animal cells!!

However, one of my old books I did a bit of subsequent searching in was a
BIOLOGY text and mentioned the yolk cell (not cells) of an ostrich egg as an
example of 'large', and human nerve cells several feet long (+ the speculation
of elephant cells being larger!). I think the ostrich egg yolk, if the facts
bear up, might well be in the running!!!

JB


I believe that the largest cell on Earth is "plasmodium of true slime mold",
 for example, Physarum polycephalum. This multi nucleated web like cell may
spread over one square meter.

YK

 If you *want* to call a seed a single cell (I'm not sure if they
qualify), there one species of cocoanut that weighs something like 40
pounds. Otherwise, it might be an ostrich egg, or, if semi-fossil eggs count,
there's some kind of preserved egg from Aussie-land that is rather larger
than ostriches. Every now and again, one turns up in decent condition.

AJH


The answer to this may well be Caulerpa, a green alga, that has essentially
one body cavity in its 6 or more foot body, although multitudinous nuclei. It
has morphological definition of organs, so it is remarkable whether it fits
the requirements of your definition or not.

The answer to this may well be Caulerpa, a green alga, that has essentially
one body cavity in its 6 or more foot body, although multitudinous nuclei. It
has morphological definition of organs, so it is remarkable whether it fits
the requirements of your definition or not.

SDH

Several years ago, there was a news article in Science (maybe Nature)
about a certain type of cell -- some sort of fungus, I think -- which
lives underground in the root system of certain trees in north-central
North America (I think).  This cell, according to the article, spreads
over a very large area, I mean like several hundred feet!  Sorry I can't
remember more, and I couldn't find it in Medline (not surprising).
Maybe someone else recalls hearing about this.

JA

If I am not mistaken, it is a ciliate and close relative of Euglena.  I believe
it was a new species discovered in Australia several years ago. It is almost
discernible with the naked eye.

LAF

I think that your suggestion of a nerve cell could be correct.  I 
remember reading that individual neurons of large mammals like an 
elephant or giraffe can grow to 3 meters in length.  You might want to 
check an encyclopedia on that.  Good luck.

MC

 I'm not sure, but check into acellular slime molds (myxomycota). 
These are multinucleate, monostromatic, and can get quite large.

J

This is an interesting question. An ovum is definitely 'large' but not that large. If a 
multinucleated coenocyte may be considered as a single cell, then a fungal hypha may be 
larger than an ovum. However, the fibrous cells that make up the supporting matrix of the 
vuscular bundles of certain plants ( eg. Gossypum sp. and certain types of hemp) are known 
to be several cm's long.  But, these cells would eventually lose their nuclei and so be 
essentially dead.

H

I may be mistaken, but I think the largest cell in volumn is the alga
called acetabulum.  I seem to remember a reference to it some few years
ago.    The longest is probably a nerve cell of one of the larger mammals,
perhaps cetaceans.  

KBJ



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