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

Monster worm and sea star frenzy

Deep under the Antarctic ice, a rare, colourful burst of starfish and 3m-long monster worms has been filmed by a BBC camera crew.Filmed in time-lapse, the extraordinary swarm of deep-sea creatures gathers to feed in a frenzy on the body of a seal, which had sunk to the ocean floor. Such a bounty of food may only occur once every ten years in the ice-cold waters of McMurdo Sound, Antarctica. The images were taken by divers filming for the natural history series Life. Descending through a hole cut in the ice, cameramen Doug Allan and Hugh Miller set up a time-lapse camera on the ocean floor. The time-lapse sequence revealed the feeding frenzy of hundreds of huge worms, starfish, brittle stars and sea-urchins.Long way down Nemertine worms, also known as boot-lace or ribbon worms, belong in their own phylum, the Nemertea. Some species are scavengers or herbivores, but most are voracious predators, catching prey using a proboscis that shoots out from their mouth. The proboscis may be poisonous or even tipped with a sticky secretion, depending on the type of worm. In Antarctica, such worms often feed on clams and shellfish. However, they also congregate with starfish, which are also called sea stars, to feed on seal droppings. In the sequence filmed for the Life series, the invertebrates gather in a frenzy to feast on a seal carcass that has sunk to the ocean floor. So much food may only arrive in one place once in a decade. The nemertine worms (Parbolasia corrugatus) are able to puncture the seal's skin with their proboscis, opening up the carcass, so that worms and marine isopods such as woodlice can enter to feed. The starfish feed more slowly - by pushing out their stomachs through their mouths. As a sea star pushes its stomach against the seal's skin, it secretes digestive juices that dissolve the seal's tissue.A burst of sea starsSea urchins, such as Sterechinus neumayeri, also get in on the act. Like the giant worms, this species comes in a variety of colours. Not only does it sometimes camouflage itself with bits of shell, but it can live for up to 40 years. Because of the cold temperatures, many creatures under the ice grow extremely slowly. But by doing so, they can reach a great age and a great size. Touching moment In temperate and tropical seas, other more common predators dominate, such as crabs. However, the fossil record shows these animals vanished from the waters of Antarctica about 35 million years ago, when the continent cooled. Today, Antarctica has no lobsters or crabs. There are also few fish, such as sharks and rays. Instead strange animals lurk there, including sea urchins, sea stars, giant worms and large underwater sea spiders, which can grow up to 30cm across and live for several decades. However, last year researchers warned that if global warming continues, it will put this unique marine life at risk.A nemertine worm's deadly proboscis In the last 50 years, sea surface temperatures around Antarctica have risen by 1-2C, which is more than twice the global average. That could encourage crabs to colonise the region, followed by fish such as sharks, which are capable of decimating the local wildlife. If that does happen, the Antarctic seafloor would no longer be dominated by soft-bodied, slow-moving invertebrates, which are believed to be similar to those found in ancient oceans prior to the evolution of shell-crushing predators. 'The Deep' episode of the BBC natural history series Life will be broadcast at 2100GMT on BBC One on Monday 30 November. BBC

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

Worm-like Marine Animal Providing Fresh Clues About Human Evolution

Research on the genome of a marine creature led by scientists at Scripps Institution of Oceanography at UC San Diego is shedding new light on a key area of the tree of life.

Linda Holland, a research biologist at Scripps Oceanography, and her colleagues from the United States, Europe and Asia, have deciphered and analyzed fundamental elements of the genetic makeup of a small, worm-like marine animal called amphioxus, also known as a lancelet.
Amphioxus is not widely known to the general public, but is gaining interest in scientific circles because of its position as one of the closest living invertebrate relatives of vertebrates. Although amphioxus split from vertebrates more than 520 million years ago, its genome holds tantalizing clues about evolution.
The research led by Holland is published in the July issue of the journal Genome Research. A corresponding research paper is published in the June 19 issue of Nature.
Holland and her colleagues studied the genes of the amphioxus species Branchiostoma floridae through samples obtained in recent years during field work off Tampa, Fla.
Because amphioxus is evolving slowly--its body plan remains similar to that of fossils from the Cambrian time--the animal serves as an intriguing comparison point for tracing how vertebrates have evolved and adapted. This includes new information about how vertebrates have employed old genes for new functions.
"We are finding that today's complicated vertebrate has not invented a lot of new genes to become complicated," said Holland, of the Marine Biology Research Division at Scripps Oceanography. "Amphioxus shows us that vertebrates have taken old genes and recombined them, changed their regulation and perhaps changed the gene function."
Originally discovered in the 1700s, amphioxus appears fish-like with a small tail fin and medial fins, but no paired ones. They spend most of their time burrowed in sand, with their snouts extended for filter feeding.
The human genome has only about 25 percent more genes than the amphioxus genome, according to Holland. During evolution, humans have duplicated genes for different functions. Such duplication has given humans and other vertebrates a much larger "toolkit" for making various structures that are absent in amphioxus, including cells for pigment and collagen type II-based cartilage, for example.
In the new research, Holland and her colleagues describe success in probing the roots of important functions such as immunity. While vertebrates have two types of immune systems--innate, which is a general first line of defense against pathogens, and adaptive, involving antibodies specific for particular pathogens--invertebrates like amphioxus have only innate immune systems. In amphioxus, several of these innate immune genes have been independently duplicated many times over. It may be that with a second line of defense, vertebrates, compared with invertebrates like amphioxus, are less reliant on innate immunity to ward off infection.
The neural crest cells of vertebrates are an excellent example of how "old" genes have acquired new functions. In all vertebrates, neural crest cells migrate from the developing neural tube throughout the body, giving rise to such structures as pigment cells, cartilage of the head and a number of other cell types. Although amphioxus has a brain and spinal cord and makes them using the same genes in the same way as vertebrates, amphioxus has no neural crest cells. Even so, amphioxus has all of the genes necessary for generating migratory neural crest cells; vertebrates have just put them together in new ways. It can be compared with a chef who takes basic leftovers in a refrigerator and whips up a fine gourmet dish.
"The take-home message from this sequencing is that the human and amphioxus genomes are very much alike," said Holland.
A collaborative effort of some 30 laboratories around the world solved the sequence of the amphioxus genome.
Further, deeper analyses between the amphioxus and human genomes in the years ahead will provide even more important clues about genetic evolution.
"All of this is just the tip of the iceberg," said Holland. "It will take a number of years for people to look in greater depth at the amphioxus and human genomes. In terms of figuring out what evolution has done and how it generally works, the amphioxus genome has really been a goldmine and will continue to be one in the years ahead."
In addition to Holland, coauthors of the Genome Research paper include: Ricard Albalat, Kaoru Azumi, Èlia Benito-Gutiérrez, Matthew J. Blow, Marianne Bronner-Fraser, Frederic Brunet, Thomas Butts, Simona Candiani, Pieter J. de Jong, Larry J. Dishaw, David E. K. Ferrier, Jordi Garcia-Fernàndez, Jeremy J. Gibson-Brown, Carmela Gissi, Adam Godzik, Finn Hallböök, Dan Hirose, Kazuyoshi Hosomichi, Tetsuro Ikuta, Hidetoshi Inoko, Masanori Kasahara, Jun Kasamatsu, Takeshi Kawashima, Ayuko Kimura, Masaaki Kobayashi, Zbynek Kozmik, Kaoru Kubokawa, Vincent Laudet, Gary W. Litman, Alice C. McHardy, Daniel Meulemans, Masaru Nonaka, Robert P. Olinski, Kazutoyo Osoegawa, Zeev Pancer, Len A. Pennacchio, Mario Pestarino, Jonathan P. Rast, Isidore Rigoutsos, Marc Robinson-Rechavi, Graeme Roch, Hidetoshi Saiga, Yasunori Sasakura, Masanobu Satake, Yutaka Satou, Michael Schubert, Nancy Sherwood, Takashi Shiina, Naohito Takatori, Javier Tello, Pavel Vopalensky, Shuichi Wada, Anlong Xu, Yuzhen Ye, Keita Yoshida, Fumiko Yoshizaki, Jr-Kai Yu, Qing Zhang, Christian M. Zmasek, Nicholas H. Putnam, Daniel S. Rokhsar, Noriyuki Satoh and Peter W. H. Holland.
Additional participants in the amphioxus genome project included Pieter de Jong and Kazutoyo Osoegawa of Children's Hospital Oakland (CHORI).
The research was funded by grants from the National Science Foundation (USA), National Institutes of Health (USA), the Wellcome Trust (UK), BBSRC (UK), MEXT (Japan), Center for Applied Genomics MSMT and Academy of Sciences (Czech Republic), and the 21th Century and Global COEs at Kyoto University (Japan), Ministerio de Educación y Ciencia (Spain), MIUR (Italy), FIRB 2001 BAU01WAFY, and from MENRT, CNRS and CRESCENDO, a European Union Integrated Project of FP6.
Adapted from materials provided by University of California - San Diego.