Scientists Use Biomedical Technique to Image Marine Worm

Scientists have for the first time successfully imaged the internal tissues of a soft bodied marine worm at high resolution using a technique borrowed from biomedical science. The findings are published in the Journal of Microscopy.

"Invertebrate worms are important for the functioning of marine ecosystems, and studies of their internal anatomy are needed to understand their physiology, ecology and evolution," explained John Dinley of the University of Southampton's School of Ocean and Earth Science based at the National Oceanography Centre, Southampton.

"Techniques such as dissection and the cutting of sections for light or electron microscopy studies are time consuming and destructive. What is really needed is a reliable, non-invasive method that can be used in the laboratory," he added.

In conjunction with Professor Ian Sinclair of the University of Southampton's Department of Engineering and other colleagues, Dinley has helped develop the use of a technique called micro-computed x-ray tomography (micro-CT) for scanning the internal structure soft-bodied marine worms.

In micro-CT scanning, the object to be scanned is rotated within a stationary x-ray beam, and magnified images are received onto a detector screen. The researchers have successfully used a bench-top micro-CT scanner to produce high-definition images of the internal structure of the predatory, burrowing worm Nephtys hombergii, specimens of which were collected from the sands of Poole Harbour.

"We believe that this is the first time this technique has been developed and successfully applied to the soft tissues of invertebrates without the use of tissue enhancing stains or radio-opaque fluids," said Dinley.

Impressive three-dimensional rotating and fly-through images have also been produced, which can be invaluable in the assessment of many aspects of functional anatomy.

As a direct result of this work, a micro-CT machine has been installed in the Natural History Museum in London. Now museum specimens or even living specimens can be scanned and their internal organs carefully examined and compared with this rapid, non-invasive and non-destructive technique.

"Large-scale comparative anatomical studies are now feasible that will lead to greater evolutionary insights," says Dinley.

The researchers are: John Dinley and Lawrence Hawkins (SOES/NOC), Gordon Paterson and Alex Ball (Natural History Museum, London), Ian Sinclair and Polly Sinnett-Jones (Dept. Engineering, University of Southampton), and Stuart Lanham (UoS/Southampton General Hospital).

J. Dinley, L. Hawkins, G. Paterson, A.D. Ball, I. Sinclair, P. Sinnett-Jones, S. Lanham. Micro-computed X-ray tomography: a new non-destructive method of assessing sectional, fly-through and 3D imaging of a soft-bodied marine worm. Journal of Microscopy, 2010; 238 (2): 123 DOI: 10.1111/j.1365-2818.2009.03335.x

Sea Worm thought to be extinct spotted off Spain

A sea worm that uses a trunk to catch prey that was thought to be extinct has been rediscovered in the waters of the Atlantic off northwestern Spain, researchers said Monday.Spanish zoologist Juan Junoy from the University of Alcala de Henares near Madrid discovered 21 of the bright red Lineus acutifrons worms at the National Park of the Atlantic Islands in Galicia, the university said in a statement."The only news we had of this species is of a description of them at an Irish beach in 1913. Since that year they had never been captured again, and the scientific validity of the description was questioned, and the species considered to be extinct," it said.The worm, which can reach a length of 25 centimetres (10 inches), is blind and uses chemical receptors to locate its prey.Unlike the massive hotel complexes found along Spain's southern coastline, the Galician coast is largely undeveloped. It features instead a maze of coves, caves and inlets that have long made it a smuggler's paradise.

Secrets Of The Sandcastle Worm Could Yield A Powerful Medical Adhesive

Scientists have copied the natural glue secreted by a tiny sea creature called the sandcastle worm in an effort to develop a long-sought medical adhesive needed to repair bones shattered in battlefield injuries, car crashes and other accidents. They reported on the adhesive here today at the 238th National Meeting of the American Chemical Society (ACS).

"This synthetic glue is based on complex coacervates, an ideal but so far unexploited platform for making injectable adhesives," says Russell Stewart, Ph.D. "The idea of using natural adhesives in medicine is an old one dating back to the first investigations of mussel adhesives in the 1980s. Yet almost 30 years later there are no adhesives based on natural adhesives used in the clinic."
The traditional method of repairing shattered bones is to use mechanical connectors like nails, pins and metal screws for support until they can bear weight. But achieving and maintaining alignment of small bone fragments using screws and wires is challenging, Stewart said. For precise reconstruction of small bones, health officials have acknowledged that a biocompatible, biodegradable adhesive could be valuable because it would reduce metal hardware in the body while maintaining proper alignment of fractures.
Stewart and colleagues duplicated the glue that sandcastle worms (Phragmatopoma californica) use while building their homes in intertidal surf by sticking together bits of sand and broken sea shells. The inch-long marine worm had to overcome several adhesive challenges in order to glue together its underwater house, and its ingenuity has served as a recipe for Stewart's research team in developing the synthetic adhesive.
Stewart's challenge was to devise a water-based adhesive that remained insoluble in wet environments and was able to bond to wet objects. The team also concentrated on key details of the natural adhesive solidification process — a poorly timed hardening of the glue would make it useless, Stewart said. They learned the natural glue sets in response to changes in pH, a mechanism that was copied into the synthetic glue.
The new glue, says Stewart, a bioengineer at the University of Utah in Salt Lake City, has passed toxicity studies in cell culture. It is at least as strong as Super Glue and is twice as strong as the natural adhesive it mimics, he notes.
"We recognized that the mechanism used by the sandcastle worm is really a perfect vehicle for producing an underwater adhesive," Stewart said. "This glue, just like the worm's glue, is a fluid material that, although it doesn't mix with water, is water soluble."
Stewart has begun pilot studies focused on delivering bioactive molecules in the adhesive that could allow it to fix bone fragments and deliver medicines to the fracture site, such as antibiotics, pain relievers or compounds that might accelerate healing.
"We are very optimistic about this synthetic glue," he said. "Biocompatibility is one of the major challenges of creating an adhesive like this. Anytime you put something synthetic into the body, there's a chance the body will respond to it and damage the surrounding tissue. That's something we will monitor, but we've seen no indication right now that it will be a problem."
Adapted from materials provided by American Chemical Society.

New Worm Species Discovered on Dead Whales

Nine previously unknown species of worms were found hiding out on whale cadavers deep in the ocean, where the worms were feasting on bone-munching bacteria. The new species are bristleworms, or polychaetes, which have segmented bodies, and are among the most common marine organisms. The worms find refuge at ocean depths, near the sea surface and even in burrows in beach sand. "First of all, I think it's very exciting to find a new species in a habitat that not many people have looked at. And then we find so many new species," Helena Wiklund of the University of Gothenburg in Sweden told LiveScience. As part of her dissertation, Wiklund identified the worms, four of which she discovered on the cadaver of a minke whale placed on the seafloor of the new national park Kosterhavet off the coast of Strömstad, Sweden. The other five species were discovered on whale bones in the deep waters off the coast of Calif. Dead whales constitute an unpredictable food source, as it's impossible to figure when and where one will die. And it's a one-shot deal. But nevertheless, when the hefty animals die, they sink to the seafloor and the payoff is big for marine species able to cash in. Scientists estimate one whale corpse provides the nutritional equivalent of 2,000-years worth of normal biological detritus sinking to the seafloor. Bristleworms are typically second- or third-shift feeders. First come the hagfish and sharks, which devour the whale's flesh. Then, bacteria colonize the skeleton and bristleworms follow. Some bristleworm species are so specialized in eating dead whales they might not survive elsewhere. For example, the bone-devouring worm Osedax is equipped with a root system that can penetrate the whale bones and helps the worm digest the fats and proteins from such bones. While the newly discovered bristleworm species didn't show any particular adaptations for feeding in this whale-carcass habitat, Wiklund says she thinks they are specialized for subsisting at whale falls or similar ecosystems.

Decoding Mysterious Green Glow Of The Sea

Many longtime sailors have been mesmerized by the dazzling displays of green light often seen below the ocean surface in tropical seas. Now researchers at Scripps Institution of Oceanography at UC San Diego have uncovered key clues about the bioluminescent worms that produce the green glow and the biological mechanisms behind their light production.Marine fireworms use bioluminescence to attract suitors in an undersea mating ritual. Research conducted by Scripps marine biologists Dimitri Deheyn and Michael Latz reveals that the worms also may use the light as a defensive measure. The report, published as the cover story of the current issue of the journal Invertebrate Biology, provides insights into the function of fireworm bioluminescence and moves scientists closer to identifying the molecular basis of the light."This is another step toward understanding the biology of the bioluminescence in fireworms, and it also brings us closer to isolating the protein that produces the light," said Deheyn, a scientist in the Marine Biology Research Division at Scripps. "If we understand how it is possible to keep light so stable for such a long time, it would provide opportunities to use that protein or reaction in biomedical, bioengineering and other fields-the same way other proteins have been used."The fireworms used in the study (Odontosyllis phosphorea) are seafloor-dwelling animals that inhabit tropical and sub-tropical shallow coastal areas. During summer reproductive events known as "swarming," females secrete a luminous green mucus-which often draws the attention of human seafarers-before releasing gametes into the water. The bright glow attracts male fireworms, which also release gametes into the bright green cloud.The precisely timed bioluminescent displays have been tracked like clockwork in Southern California, the Caribbean and Japan, peaking one to two days before each quarter moon phase, 30 to 40 minutes after sunset and lasting approximately 20 to 30 minutes.Deheyn and Latz collected hundreds of specimens from San Diego's Mission Bay for their study, allowing them to not only examine live organisms but also produce the fireworms' luminous mucus for the first time in an experimental setting. The achievement provided a unique perspective and framework for examining the biology behind the worm's bioluminescent system.A central finding described in the Invertebrate Biology paper is that the fireworms' bioluminescent light appears to play a role beyond attracting mates. The researchers found that juveniles produce bioluminescence as flashes, leading to a determination that the light also may serve as a defensive mechanism, intended to distract predators.Through experiments that included hot and cold testing and oxygen depletion studies, Deheyn and Latz found that the bioluminescence is active in temperatures as low as minus 20 degrees Celsius (minus 4 degrees Fahrenheit). Higher temperatures, however, caused the bioluminescence to decay rapidly. The light also proved resilient in settings of low oxygen levels.Based on these tests, the researchers believe the chemical process responsible for the bioluminescence may involve a specific light-producing protein-also called a "photoprotein." Further identification and isolation will be pursued in future studies."We were inspired by the work of earlier researchers who had studied the chemistry of fireworm bioluminescence, including Osamu Shimomura, one of the winners of the 2008 Nobel Prize in Chemistry for his discovery of green fluorescent protein from the jellyfish luminescent system," said Latz. "This new study showed that the fireworm bioluminescence also involves green fluorescence, originating from the oxidation product of the luminescent reaction."The study was supported by a grant from the Air Force Office of Scientific Research's Biomimetics, Biomaterials and Biointerfacial Sciences program.Source: University of California - San Diego

Synthetic Sea Worm Glue May Mend Shattered Knee, Face Bones

Sandcastle worms live in intertidal surf, building sturdy tube-shaped homes from bits of sand and shell and their own natural glue. University of Utah bioengineers have made a synthetic version of this seaworthy superglue, and hope it will be used within several years to repair shattered bones in knees, other joints and the face.

"You would glue some of the small pieces together," says Russell Stewart, associate professor of bioengineering and senior author of the study to be published online within a week in the journal Macromolecular Biosciences.
"When you break the top of a bone in a joint, those fractures are difficult to repair because if they are not aligned precisely, you end up with arthritis and the joint won't work anyway. So it's very important to get those pieces aligned as well as possible."
In lab tests using cow bone pieces from groceries, the synthetic sea-worm glue – a first-generation prototype – performed 37 percent as well as commercial superglue.
Stewart expects the synthetic worm glue will be tested on animals within a year or two, and will be tested and used on humans in five to 10 years.
The synthetic sandcastle worm glue would not be used to repair large fractures such as major leg and arm bones, for which rods, pins and screws now are used. But Stewart envisions that it might be used for gluing together small bone fragments in fractured knees, wrists, elbows, ankles and other joints, and also the face and skull.
"If a doctor rebuilds a joint with pins and screws, generally weight is kept off that joint until it's healed," Stewart says. "So our goal isn't to rebuild a weight-bearing joint with glue. It is to hold the pieces together in proper alignment until they heal. … We see gluing the small fragments back into the joint."
In their study, Stewart and colleagues wrote: "It is especially difficult to maintain alignment of small bone fragments by drilling them with screws and wires. An adjunctive adhesive could reduce the number or volume of metal fixators while helping maintain accurate alignment of small bone fragments to improve clinical outcomes."
Bioengineer Patrick Tresco, associate dean for research at the University of Utah's College of Engineering, says: "Most current adhesives do not work when surfaces are wet so they are no good for holding together bone, which is wet and bloody. There is nothing like it [the synthetic worm glue] on the market today."
The synthetic glue also can carry drugs, so it could be used to deliver pain killers, growth factors, antibiotics, anti-inflammatory medicines or even stem cells to sites where bone fragments are glued, "simultaneously fixing the bone and delivering potent drugs or even genes to the spots where they are needed," Stewart says.
And where pieces of bone now are cut out due to cancer, the adhesive might be used to firmly attach "tissue scaffolds" used to encourage regrowth of the missing bone.
Stewart is seeking to patent the synthetic sea worm glue so it can be licensed to an outside company that would develop it as a product. He hopes to make better versions that have more bonding power, are biocompatible in the human body and biodegradable.
"Ultimately, we intend to make it so it is replaced by natural bone over time," Stewart says. "We don't want to have the glue permanently in the fracture." Stewart says some synthetic superglues or "instant glues" are used instead of sutures for superficial skin wounds. But because of toxicity or toxic byproducts, "they are not suitable for deep tissue use," including bone repair, he adds.
Building a Sandcastle Colony 'One Grain of Sand at a Time'
Stewart conducted the study with Hui Shao, a doctoral student in bioengineering; and Kent Bachus, a research associate professor of orthopaedics.
The study involved Phragmatopoma californica, the sandcastle worm, which lives in vaguely sandcastle-like colonies of tube-shaped homes on the California coast.
The adult worm is an inch or so long, and an eighth-inch in diameter. But they build tubes several inches long, using sand grains and shell fragments.
"They will not leave their tube. They live in their tube and have dozens of tentacles they stick out one end of the tube, which is how they gather food and particles to build their shells with."
Tiny, hair-like cilia brush the sand grains and shell pieces down the tentacles so they can be grabbed by the worm's fleshy, pincer-like "building organ" and glued onto the under-construction tube piece by piece.
The worm "secretes two little dabs of glue onto the particle," says Stewart. "And the building organ puts it onto the end of the tube and holds it there for about 25 seconds, wiggling it a little to see if the glue is set, and then it lets go. The glue is designed to set up and harden within 30 seconds after the worm secretes it."
Worms build their tube-like shells next to each other, like stacks of pipes, to form a large colony. "One grain of sand at a time it builds big, reef-like colonies the size of Volkswagens," Stewart says. "A colony looks like a mound."
In the lab, Stewart previously showed the worms will use any handy building material, using their natural adhesive to build tubes by gluing together tiny pieces of egg shell, glass beads, red sand, bone, zirconium oxide, and even pieces of a silicon chip.
The Chemistry of Glue
Scientists already knew sandcastle worm glue contained proteins and a substance named dopa, which also is present in glue mussels used to glom onto rocks and boats.
"But we took the compositional characterization a lot further," hypothesized how the worm glue works, and used that to create the synthetic glue, says Stewart.
The sea worm's glue is made from two proteins – one acidic or negatively charged, the other basic or positively charged – that are natural polymers, or compounds with a repeating, chain-like structure. The glue also contains positively charged ions of calcium and magnesium.
In the natural worm glue, each protein polymer's "backbone" is made of polyamide, which has "side chains" of other chemicals attached to the backbone.
Stewart didn't use polyamide in the synthetic glue because it is impractical to synthesize. Instead, for the "backbone" of polymers in the synthetic glue, he used water-soluble polyacrylates, synthetic polymers that are related to commercial superglues and are used in floor wax, nail polish, pressure-sensitive adhesives and Plexiglas.
The "side chains" attached to the synthetic glue's polymer backbones copied the natural worm glue's side chains chemically and in other ways, Stewart says. Some side chains are dopa, which makes the glue function as glue.
"We made polymers with side chains that mimicked the positive and negative charges in the worm glue," Stewart says.
When the polymers are mixed, they form an unusual substance known as a "coacervate," which condenses out of the polymer solution and sinks to the bottom of a test tube as a dense solution that is the foundation of the synthetic glue.
The two polymers in the coacervate "cross link" – their side chains attach to each other – forming chemical bonds that make synthetic worm glue harden.
Because the solution-within-a-solution doesn't disperse, it can be sucked up with a syringe. "In some cases we may be able to repair bones with a [glue-filled] syringe rather than screws and power tools," says Stewart.
To test the strength of the synthetic glue, Stewart cut cow leg bones from grocery stores in cubes measuring 0.4 inches on a side, sanded the pieces, got them wet and bonded pieces together either with synthetic worm glue or with Loctite 401 superglue. The bonded pieces of bone were kept warm and wet for 24 hours. He tested the strength of the glues by using dull blades to push each of the glued cubes in opposite directions until the bond failed.