Tuesday, March 27, 2012

What Good Are Echinoderms? Pt. 2! Biotechnology!

Every few years, I get this REALLY annoying question in one form or another...
"Other than evolution, ecology, paleontology, genetics, and marine biology, echinoderms aren't really good for anything are they?"
*sigh* Several years ago, I wrote up something that answered the question "Echinoderms... So, what good are they??"

Its been a few years and the question has once again reared its ugly head. Plus, its always good to re-visit the directions that research may take you..

And so I thought I would present how echinoderms have found their way into several important uses/functions in the rapidly growing field of biotechnology!

And on this post, we don't even TOUCH on all of the ways that echinoderms have been used in Biomimicry! (we'll save that for another post!)

Information below was inspired by two papers! This one by C. Petzelt (Are Echinoderms of Interest to Biotechnology?) which you can find on Google books here. and this paper by Micael et al. (2009) on Exploitation and Conservation of Echinoderms.

1. Sources of Anti-Cancer drugs
There is currently a substantial effort to discover marine biodiversity that may serve as sources for anti-cancer, anti-AIDS and other disease resistant medicines.

There are big research programs, such as the one that was underway at the Coral Reef Research Foundation in Palau (in conjunction with the National Cancer Institute) to discover potentially important materials throughout tropical coral reefs and many other places throughout the world.

One report from Mutee et al. published this year in the African Journal of Pharmacy and Pharmacology claims to have found a valuable anti-cancer agent in what has been a reviled pest and predator of coral... Acanthaster planci the Crown of Thorns Starfish!
(A. planci image from Wikipedia)
Mutee and colleagues have found that an extract from the Crown of Thorns starfish inhibited cell growth and induced "cell death" (called apoptosis) in a breast cancer cell line. Apparently, this cell death effect was more potent and faster than the one created by tamoxifen (another well known anti-cancer agent).

The authors hope that "...A. planci starfish extract may be utilized as a potential chemotherapeutic agents in the treatment of human breast cancer." It would be an interesting turn of events given Acanthaster's long history as a coral reef predator and "villain"...

2. Sources of anti-bacterial drugs.
A 2002 paper in the Journal of Invertebrate Pathology by Haug et al. studied 3 different echinoderms from Norwegian waters for antibacterial properties! the sea cucumber Cucumaria frondosa..
Image from SERPENT Media via the Encyclopedia of Life!

and the green sea urchin, Strongylocentrotus droebachiensis..

Haug and his team found that extracts from all 3 of these species made from the body wall and in the body cavity fluid, as well as eggs and gastrointestinal organs that all showed some antibacterial activity.

These weren't the first echinoderms to show antibacterial activity..with prior accounts showing brittle stars and sea cucumbers all displaying potential.

Haug and other studies found that many echinoderms display very effective lysozyme activity. Lysozymes are special enzymes that attack the cell walls of bacteria. Naturally occurring lysozymes might play a role in the defensive responses of different species.

Compounds within also showed the potential for hemolytic compounds which might be useful as blood thinning agents.
Ultimately, there was a great potential for all of these -but especially the antibacterial compounds that, upon further refinement and purification might lead to potentially "novel antibiotics"!

3. Anti-Fouling Chemicals.

Have you ever noticed how starfish and other echinoderms can just kinda sit there-but NOTHING GROWS ON THEM??

You don't ever see algae, barnacles, sponges, or any other kind of "fouling" organisms that settle out and instantly begin colonizing bottom substrates.

Well, it turns out there's a bunch of people who got interested in that question.. and a few studies by Jana Guenther and colleagues. (It should be noted that there were several other studies before Guenther as well..)

Many of their papers such as this one and this one have shown that chemicals produced by some sea stars may be one reason. Some of their study animals included the common "Blue Linckia" aka Linckia laevigata found throughout the Indo-Pacific.
Photo by Tim Hochgrebe via Flickr
The very attractive Fromia indica....
Indian Sea Star
And the so-called "fake Astropecten" Archaster typicus which occurs throughout the Indo-Pacific.
Common sea stars (Archaster typicus)

Photo by Wild Singapore

Guenther found from experiments that several chemicals, including hexadecanoic acid, cholesterol, lathosterol, and sitosterol were all extracted from individuals and used to prevent the settlement of diatoms on the sea star surfaces.

These then have the potential to be used as possible treatments to prevent "fouling" on ships and ports. But again, work that requires further purification and experimentations...

4. Bionics! 
The crystal "eyes" of Brittle Stars! This is actually an older discovery from a paper in Nature from 2001! (which you can read by clicking here).
(from the NMNH collection via EOL)
Brittle stars, as it turns out have tiny calcite lenses that are present all over the surface of the disk! They look like this...
(photo by Joanna Aizenberg from Wyss Institute, Harvard)

Aizenberg and her colleagues found that thousands of these lenses form a compound eye that covers the surface of the animal, resulting in "a functon similar to a digital camera that builds up the picture pixel by pixel".

This is apparently the inspiration for engineers in the "photonic industry" who have been trying to imitate these lenses for general use...

5. And there's many more...
I was actually able to stumble upon several more but none were worthy of a separate account so here's a short summary...
Note that ALL of these applications had their roots in more fundamental parts of biology-ecology, evolution and systematics. Some of these bioactive compounds are used in defense. Or are part of the animal's own immune system.

I would advise never to lose sight of the fact that "useful" science originates from more fundamental questions about the animal that started with the far more important interrogative

"Hmm..that's interesting..."

Monday, March 26, 2012

Tropical Sea Cucumber Vs. Maru the cat!

UPDATE! thanks to Dave Pawson for the citation! Go to this open access paper by Peter Glynn from 1965 on "Active movements and other aspects of biology of Astichopus and Leptosynapta. Biol. Bull. 129: 106-127." to read the full account!
From the abstract: Astichopus does this in response to sudden changes in changes in salinity concentration, oxygen deficiency and other "bodily disturbances." The movement below may be a prelude to evisceration.. which I've discussed here.

The Strange Rolling Behavior of Sea Cucumbers.. now with UPDATED further videos! 

and MORE! (updated March 2022!)
Internet sensation Maru doing what he does...
Now who is doing more? Should a sea cucumber be more active than a cat? :-)
Seriously though, I've never heard nor seen of a sea cucumber doing that rolling in the sand action. I this another thing that naturalists see that may not have been recorded before??

Tuesday, March 20, 2012

More on Using Flickr to crowdsource new biodiversity! How many South African Starfish can we find?

Can we discover what and where species live by using holiday pictures and dive photos??
I recently saw that a recent newsbit here featured the range extensions of some "rare" or more precisely seldom encountered species including Astropecten regalis, Meyenaster gelatinosus, and the big orange spiny one called Paulia horrida

Truth be told, all 3 of these species are found in that tropical east Pacific area..and so, finding them in Peru (a poorly studied area) is really not much of a surprise..

BUT, I thought..wouldn't it be interesting if I did something just like this..but just using Flickr!! Using the accumulated pictures from people all around the world? Divers! Vacationers! Photographers! Aquarium goers!

Can we crowdsource biodiversity using the Internet??

Let's find out.

Some dynamics...

1. I do not own any of these images. These have all been "crowdsourced" from Flickr and are available here via the embed code for each picture. They have NOT been uploaded.

2. Animals are sometimes difficult to identify from pictures.

3. Why South Africa? South Africa is unusual in that it occurs right at the confluence between the tropical south Indian Ocean, the south Pacific, and the subAntarctic..so there's an interesting temperate water mix of animals that you really don't find anywhere else in the world. Its very distinctive.
map from Wikipedia!

Plus, its a suitably exotic fauna (at least to those of us not in South Africa!) that its interesting to readers.

Thanks to generous photographer Bernard Picton I was able to show off some rarely seen South African species awhile back. Click here to see!

New Records or maybe even new species?

Neoferdina or Paraferdina? (Goniasteridae) from Aliwal Shaol, KZN, South Africa

Further examination of a specimen would be necessary..but this is an intriguing possible new record..
starfish x
photo by Geoff Spiby on Flickr

Here's an Anthenea or some oreasterid that I haven't been able to ID to species.. Again, the literature has no record of an animal of this kind from South Africa per se.. But this is at the northern range.

Note also the little parasitic white snail living on the top!
Starfish on the reef
Photo by Genna S on Flickr

Here are some of the more frequently encountered species...
Family Asterinidae-Patiriella dyscrita (H.L. Clark, 1923)

A temperate, shallow water "cushion star".
2009 01 08 - 00500 [6757]
2009 01 08 - 00501 [6758]
The above two images by by Chris Liberty, on Flickr

Family Asterinidae-Callopatiria granifera Gray, 1847 from South Africa
Not much known about it-but occurs in more temperate waters.
Granular starfish (Austrofromia schultzei)
Above two photos by Derek Keats on Flickr

Starfish macro
by Coda on Flickr

Family Echinasteridae-Henricia ornata (Perrier, 1869)

Not much known about it-but occurs in more temperate waters.
Granular starfish (Austrofromia schultzei)

Family Oreasteridae-Culcita schmideliana (Retzius, 1805) from Rynie, Kwazulu Natal

This is closely related to the widespread cushion star Culcita novaeguineae which occurs in the Pacific. Culcita schmideliana occurs primarily in the Indian Ocean in shallow, tropical reef habitats.

This species is differentiated by the large distinct tubercles..
photo by cathm2 on Flickr

Family Oreasteridae- Pentaceraster mammilatus (Audoin, 1826)

A widely distributed starfish in Oreasteridae. Tropical, shallow-water species. Closely related to Protoreaster nodosus which is found in the tropical central Pacific.

Full biology is poorly understood but possibly a microalgal film feeder..
Starfish 3
both images by jovdam on Flickr

A rather curiously colored Choriaster granulatus
Image by Mark Kenny
Ferdina sadhensis Marsh & Campbell, 1991 Umkomaas, Kwazulu Natal, South Africa

This species was only recorded from South Africa in 1996 and was originally described from Oman from only 5 specimens!
Sea Star
photo by BBM Explorer on Flickr
Sea star at Aliwal Shoal, KwaZulu-Natal, South Africa
photo by Derek Keats on Flickr
Starfish 2
photo by jovdam on Flickr

Family Goniasteridae-Fromia elegans H.L. Clark 1921

Widely distributed throughout the Indo-Pacific. A tropical shallow water species.
photo by Henry & Tersia, on Flickr

Red starfish
photo by genna S on Flickr

Family Asteriidae Marthasterias glacialis (Linnaeus, 1758)

A widespread temperate water species. It occurs from the North Atlantic on the European coast down to South Africa. Feeds on bivalves and other mollusks.
Knysna, South-Africa (23/04/07)
Image by Jinnie Lips
Atlantic (8)

photo by jtresfon, on Flickr
photo by aimless shears on Flickr
starfish sculpture

photo by Mark Jutton on Flickr
So, that's 10 species here..plus Calliaster baccatus from my earlier Echinoblog. But here's a new pic from Haerlem Wreck
Cobbled Starfish (Calliaster baccatus)
Photo by Photopixie2
There was a time when folks would have to be a world expert scientist or diver to see South African species of ANY thing.

Amazingly, (if you know what to look for) today you can find nearly a dozen species of starfish just by browsing through a photostream!!

Here's a cool looking Basket star for good measure!
One of my favourite underwater creatures - a Basket Star (Astrocladus euryale)
By Photopixie2

Tuesday, March 13, 2012

Sand Dollars ARE Sea Urchins. Please make a note of it!

Eccentric Sand Dollar (Alive) - Dendraster excentricus
photo by Cheryl Moorehead
So, last week, I was contacted by an intrepid member of the public who was quite interested in finding out more about sand dollars.. But apparently, the curiosity of this fellow had been stymied by the internet!

GASP! Who would have thought that there could be a lot of questionable and apparently, conflicting information on the Internet!!!

A lot of info on these animals may be somewhat basic to the well-travelled marine biologist, but maybe not so much to the curious or intrigued student or aspiring beach scholar! So, I thought today I would explain some basic sand dollars "stuff" and clarify some of the mystery.

FIRST-some basic introductions.....

So, everyone is at least passingly familiar with sand dollars.

Those funny "dollar shaped shells" that one often finds walking along a beach down by the sea shore. How often have you seen this familiar sight?

Sand dollar at Lover's Key State Park
photo by Jdigeronimo66
So, let's clarify this first- and foremost.

Sand dollars are the skeletons from ANIMALS.

Specifically, they are Echinoderms, which is the group that includes starfish, sea cucumbers, crinoids, and of course... sea urchins.

When sand dollars are alive, they are covered with a "fuzz" and look like this..
Eccentric Sand Dollar (Alive) - Dendraster excentricus
photo by Cheryl Moorehead
But following a little erosion and/or natural "cleaning" of the "fuzz" what you get is the internal skeleton:
Eccentric Sand Dollar (Dead) - Dendraster excentricus
photo by Cheryl Moorehead
And what you are seeing? is an INTERNAL skeleton (aka an endoskeleton) This even includes the spines (i.e., the "fuzz") because ultimately all of that (body skeleton+fuzz) is covered by a thin layer of skin or epidermis.

The "fuzz" are actually the SPINES on a very strange looking sea urchin!

Sand dollars are ANIMALS, specifically they are sea urchins! (Class Echinoidea) 

Sand dollars belong to a group known as the Clypeasteroida. There are some 75 genera of sand dollars, 29 living and 49 fossil (following Mooi 1989) with quite a few species.

Most sand dollars live in tropical shallow-water places (e.g., Africa, Singapore, Indonesia, the Bahamas, etc) but a few do live in cold to temperate waters (e.g.,
Dendraster excentricus on the west coast of North America)

Sand dollars are NOT shells. Proper shells are deposited by organisms (such as mollusks) and are external to an animal's body.

And while we're discussing this, please note that sand dollars have ENDOSKELETONS rather than exoskeletons. That is to say, they are covered by skin and are considered "inside" the animal's body. A Sand dollar skeleton is known as a TEST.

So What makes a sand dollar a sea urchin??

Typically, we think of conventional sea urchins as looking kind of like this...
Sea Urchin
A big sized, ROUND ball covered by spines. These sea urchins often graze on algae an live out in the open on reefs or kelp beds. Often in large numbers.

These have historically been referred to as "Regular" urchins. They have long, well-developed Spines and well-developed teeth as part of a elaborate jaw called Aristotle's Lantern. You can see all of these features in this video...

Now, in CONTRAST....
Sand dollars are members of a specialized sub-group of sea urchins that are often referred to as the "Irregular Urchins" These urchins differ quite a bit from the so-called "Regular" urchins because they show a suite of adaptations to living in sandy/muddy/ bottoms!
In "irregular" sea urchins.. specifically sand dollars the following changes occur...

1. The body (i.e., the test) changes from round and radial (in regulars) to flat and bilateral (in irregulars) like this...
Sea urchin shell

(photo by Electropod)

to something more like this, which you'll note has both a left and a right side..
Sand dollar on the beach

(photo by Avian-Cetacean Press)

2. Spines in "regular" urchins are usually elongate and pointed. But those in "irregular urchins" (esp. sand dollars) are short and specially modified to help in moving sediment..like so...

Here's what a single spine looks like under SEM close up. Not pointed but with a more blunt tip...

3. The special jaw apparatus "Aristotle's Lantern" is modified!

In a "regular" sea urchin, the Aristotle's Lantern or Jaw (seen here from the inside with the rest of the body removed) is used to feed on algae and its positioned as such..
Here's a neat video that shows the oral surface-and you can see the jaw's teeth in action emerging from the mouth

In contrast..here's the jaw (aka the Aristotle's Lantern) from a sand dollar. The top has been cut away and you can see it from the inside (mouth facing bottom). Its been modified into basically, a "crushing mill" for grinding up sand and so forth.
Here's a picture to show you more of what the "jaw" is like in other species.
the starfish within

The individual pieces of the jaw (aka the Aristotle's Lantern -which are often broken) is probably what you hear rattling around inside when you pick one up off the beach...

Plus, you'll often see it used in "inspirational" art and the famous "Legend of the Sand Dollar" postcards and related paraphenalia like this one...
The "doves of peace" are the broken fragments of the Aristotle's Lantern, i.e, the jaw the animal used to crush and grind sand. The "Star of Bethlehem" is a neatly dissected, complete jaw from the inside of the sand dollar.

5. The Body shape has changed as the body as evolved from that of a "regular" to an "irregular" urchin.
The above tree is used from Mooi, 1990 in Paleobiology!

The overall shape has seen a flattening out in the upper right part of the tree where we see sand dollars relative to their more globose relatives.

If you want to read an excellent paper on the evolution of sand dollars, I would suggest checking out this paper by Rich Mooi in Paleobiology. Its from 1990 but has many interesting bits!

Here's a kind of loosey goosey summary diagram  by Echinoblog Art Dept!
So again..
The "Regular" urchin or ancestor:
1. Grazes on algae or other items. Many live out in the open. Several species live on reefs or on kelp beds.
2. Test (the body) is round, globose and pentameral (that is -radial in 5 directions)
3. Spines are elongate.
4. The Aristotle's Lantern is larger and generally, is used to graze off bottoms

BUT if you compare the SAME features in Sand dollars and other "Irregular" urchins...
1. Lives on sandy or other bottoms with lots of sediments or mud.
2. Test is often flattened, and bilaterally symmetrical
3. Spines are shorted and appear "fuzzy" on the surface
4. The Aristotle's Lantern is flattened and specialized for grinding sand.

Remember that the above differences are morphological ADAPTATIONS that are specifically tied to living and digging through the sandy, bottom habitat.

The spines and Aristotle's Lantern see clear modification for a specific lifestyle... In many ways, this is a beautiful example of how morphology has changed as adaptation to a specific life mode.

Sand dollars have many NEAT adaptations to living on sandy bottoms.

For example, this one and this one are used to keep it from getting washed away..

Cloning in sand dollar larvae as a defense!

Sand dollars are basically, REALLY strange sea urchins! Please make a note of it!

Sunday, March 11, 2012

The Origami Echinoderm Tree of Life

This is REALLY neat! Overall, the tree is phylogenetically accurate and the origami representations are AMAZING!
Although obviously, still missing sea cucumbers and feather stars (the author has a cool origami stalked crinoid!)

My thanks to reader Tentaculus for sending me to the original source page on origami animals (and esp. showing different origami echinoderms), including one or two Paleozoic echinoderms! Go to this by clicking here: (http://t-usuda-origami.blog.so-net.ne.jp/archive/c2300418772-1)