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(Bio) Snails That Fly Around the World (Mollusks)

 
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PostPosted: Thu Jan 26, 2006 7:22 am    Post subject: (Bio) Snails That Fly Around the World (Mollusks) Reply with quote






This is a lesson on the phylum mollusk. Perhaps, one of its members that you maybe familiar with is the snail. The first three links found at the end of the news article are excellent pages for snails:

http://www.kiddyhouse.com/Snails/
http://library.thinkquest.org/TQ0312800/snail.htm
http://www.weichtiere.at/Mollu.....dschn.html

The news article talks about how snails are able to go around the world. Snails do not fly but they are able to get a free ride from birds. Find out how snails are able to do this by reading the news article.

There are also links provided that point to the work of Baldomero Olivera, a Filipino American, who is now a distiguished professor of biology in Utah. Professor Olivera is the world's expert on cone snails.



Snails That Fly Around the World
By Bjorn Carey
LiveScience Staff Writer
posted: 25 January 2006
01:01 pm ET

The chicken may have just wanted to get to the other side of the road, but here's a real puzzler:

Why did the snail travel 5,500 miles from Europe to an island in the South Atlantic?

New research reveals that it was most likely stuck to a bird.

Snails of the genus Balea are found throughout Europe and the Azores, the group of islands in the middle of the North Atlantic, and similar snails can be found on a tiny island chain in the South Atlantic. Because of the enormous distance between these two groups, scientists have long believed they belonged to a different genus, Tristania.

Now, genetic and anatomical analyses show that the Tristania snails are actually members of the Balea genus.

Round-trip

The study indicates that Balea snails somehow traveled from Europe to the Azores and evolved into two different species. Then, some packed up and headed 5,500 miles south to Tristan da Cunha, where they further differentiated into eight more species.

Finally, Balea snails from Tristan returned to Europe, where until recently they have been mistaken as the Balea perversa snails that made that original trip.

The question remains, though, how did these snails cross the ocean?

"Traveling to the South Atlantic is quite problematic for a very pedestrian snail," study co-author Richard Preece of the University of Cambridge told LiveScience.

It seems they didn't go by boat, the preferred mode of transport for some invasive species.

Humans didn't discover Tristan da Cunha until 1506, and didn't permanently settle there until 1816. Even today, these islands are home to only some 300 people. And it seems clear that the snails were around well before then, based on the lengthy period of time it would have taken for these new species to radiate from the original travelers.

"This clearly has nothing to do with human agency," Preece said. "These dispersal events happened long before humans were around."

Sticky solution

If there's one thing Balea snails do exceptionally well, it's produce super-sticky slime. They're very seldom found on the ground, and mostly inhabit trees. Researchers think that the snails get from tree to tree by hitching rides on birds, and the same may be true for stealing a ride to a tropical island.

"I think because they live in trees and are particularly sticky, they're prone to being carried by birds," Preece said.

Identifying the particular bird that served as a snail airline from the north to south Atlantic poses a challenge.

Most of the migratory birds that cross the equator, such as arctic terns and great shearwaters, don't come to shore often.

"Trying to get one of those birds and the snails together is problematic," Preece said. "So I suspect that some type of wading bird, with a cargo of stowaway snails tucked into its feathers, was blown off course by a storm and deposited the snails on these islands."

Hurricanes and other strong storms have been known to blow spiders and insects over the ocean, but Preece thinks this mode of transport is highly unlikely for snails. He also rules out the possibility of them rafting on floating vegetation, partly because the distance is so great, but also because of an experiment by Charles Darwin, who was also curious about how snails island-hop.

"Darwin stuck snails on ducks' feet and submerged them in seawater and found them to die quickly on exposure," Preece said.

All it would take is one snail to start a village, though. Balea snails are hermaphroditic, so they can reproduce all by themselves and release baby snails from their shells.


*************************************************************

Questions to explore further this topic:

What are snails?

http://www.kiddyhouse.com/Snails/
http://library.thinkquest.org/TQ0312800/snail.htm
http://www.weichtiere.at/Mollu.....dschn.html

A story with a similar plot: How did some snails reach Australia?

http://www.amonline.net.au/factsheets/snails.htm

Image gallery of snails

http://members.tripod.com/arnobrosi/gallery.html

Farming edible snails

http://www.rirdc.gov.au/reports/NAP/03-137.pdf

Snails could become pests too

http://www.pmra-arla.gc.ca/eng.....ils-e.html

Snails can give you worms

http://www.abc.net.au/science/.....704700.htm

Images of some sea snails

http://www.woodbridge.tased.ed.....snails.htm

Cone Snails

http://www.portfolio.mvm.ed.ac.....nails.html

Baldomero Olivera: World's Cone Snail expert

http://www.bioscience.utah.edu.....ivera.html
http://www.livescience.com/ani.....41031.html
http://www.mbl.edu/publication...../cone.html
http://home.arcor.de/be/bethge/conesnails.htm

What are mollusks? (phylum)

http://www.woodbridge.tased.ed.....llusca.htm
http://www.amonline.net.au/inv...../index.htm
http://www.conchologistsofamerica.org/conchology/

Images of mollusks

http://www.molluscan.com/shellimages/

What are shells?

http://www.conchologistsofamerica.org/theshells/

What is Gastropoda? (class)

http://animaldiversity.ummz.um.....opoda.html

GAMES

http://www.nationalgeographic.com/kids/games/
http://www.geocities.com/sseagraves/snailgames.htm


Last edited by adedios on Sat Jan 27, 2007 3:44 pm; edited 3 times in total
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PostPosted: Tue Feb 21, 2006 12:16 pm    Post subject: Giant snails destroy crops in Surigao Sur Reply with quote

http://news.inq7.net/regions/i.....y_id=66958


Giant snails destroy crops in Surigao Sur
First posted 10:26pm (Mla time) Feb 22, 2006
By Bert Pacate
Inquirer


TANDAG, SURIGAO del Sur -- Hundreds of hectares of rice farms in the province were flattened in what officials described was an invasion of giant snails.

The provincial agriculture office said the infestation was triggered by floods that swept the province and several areas of Caraga.

Marco Quico, provincial agriculturist, said at least 15 towns suffered from the infestation -- Barobo, Bayabas, Cagwait, Cantilan, Carmen, Carrascal, Cortes, Lanuza, Lianga, Madrid, Marihatag, San Agustin, San Miguel, Tago and this town.

“In the past years snail infestation of rice lands was very minimal,” he said.

Quico said heavy rains in the past three weeks brought the snails out. They are normally dormant during the dry season.

“We have to replenish the damaged plants or there will be a shortage of rice this year,” he said.

Quico warned of a price increase in case of a shortage.

He said he requested for rice seeds to be given to farmers.

Quico also urged farmers to help remove the snails manually, put them in sacks and burn them.

The golden snail is a native of South America.

It was introduced into the country by the Marcos regime in the 1980s to boost food security and provide an alternative source of protein.
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PostPosted: Thu Jul 27, 2006 6:41 am    Post subject: What Makes Sea Creatures Large or Small Reply with quote

What Makes Sea Creatures Large or Small

By Abigail W. Leonard
Special to LiveScience
posted: 26 July 2006
10:11 am ET



From tiny barnacles to giant squid, the sea is home to creatures of every weight class. Now scientists think they’ve found a connection between aquatic animals’ habitats and their size.

Researchers have long tried to identify a pattern that could explain the varying sizes of sea creatures. Analyzing snails in particular produced a great deal of data but few leads. Marine biologists found big snails lurking in the depths and big snails close to shore. Likewise, small snails are found in both areas.

That might sound like a dead end.

But one enterprising scientist chose to frame the question differently.

For the full article:

http://www.livescience.com/ani....._size.html
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PostPosted: Fri Aug 11, 2006 7:31 am    Post subject: Mussels evolve quickly to defend against invasive crabs Reply with quote

University of New Hampshire
10 August 2006

Mussels evolve quickly to defend against invasive crabs

DURHAM, N.H. – Scientists at the University of New Hampshire (UNH) have found that invasive crab species may precipitate evolutionary change in blue mussels in as little as 15 years. The study, by UNH graduate student Aaren Freeman with associate professor of zoology James Byers and published in the Aug. 11 issue of the journal Science, indicates that such a response can evolve in an evolutionary nanosecond compared to the thousands of years previously assumed. The paper is called "Divergent induced responses to an invasive predator in marine mussel populations."

"It's the blending of ecological and evolutionary time," says Freeman, a Ph.D. candidate in the department of zoology. "It's an important development in the arms race between these crabs and these mollusks." Crabs prey on blue mussels by crushing their shells.

Freeman looked at the inducible defense – shell thickening – of blue mussels (Mytlius edulis) in the presence of two invasive crab species in New England, the Asian shore crab Hemigrapsus sanguineus and the green crab Carcinus maenas. While Carcinus was introduced to New England from Europe between 150 and 200 years ago, Hemigrapsus is a relative newcomer, arriving from Asia to New Jersey in 1988. While previous research had established that mussels recognize Carcinus, it had not be determined if they recognize Hemigrapsus. And, crucial to the design of Freeman's study, Hemigrapsus is not present north of mid-coast Maine.

"This set up a chance to look at populations that had been exposed to the predators for varying lengths of time," says Freeman. "We wanted to know, how is it that these mollusks can recognize a crab that is historically not present in North America?"

Freeman exposed mussels native to the northern – above mid-coast Maine – and southern New England to both Carcinus and the Hemigrapsus. Both populations thickened their shells when exposed to waterborne cues of Carcinus, but only the southern mussels – Freeman describes them as "more worldly" – expressed inducible shell thickening in the presence of Hemigrapsus.

"The mussel's inducible response to H. sanguineus reflects natural selection favoring the recognition of this novel predator through rapid evolution of cue specifity or thresholds," Freeman and Byers write.

Findings were consistent in two experiments over two years, one in a laboratory setting in Nahant, Mass., and one in the field at Woods Hole, Mass. "The consistency over two years and two sites really suggests an underlying robust mechanism," says Byers, who is Freeman's dissertation advisor.

While this sort of rapid evolutionary response to predators has been exhibited in some other species, all have been vertebrates. The blue mussel, which Freeman describes as the lab rat of marine biologists, is an invertebrate "that people assume is not very bright," he says. Yet his findings indicate that within the brief span of 15 years, it has evolved an inducible response to a new predator.

How do mussels evolve so quickly? In southern New England, the scientists say, mussels are prey to many crabs as well as other marine species. "When Hemigrapsus came along the mussels' wheels were well-greased to respond," says Byers. "That's our best guess."

Byers helps put the impact of the research in context. Because extensive data does not exist on invasive ecology, "there's a tendency to extrapolate any data you get on an invasive species. But here we show that the response from the prey differs over just a couple hundred kilometers."

And while its "real world" impact is not immediately obvious, Byers suggests that perhaps northern Maine and Canadian shellfishers might consider "beefing up the worldliness of their naïve mussel populations before the Hemigrapsus arrives," he says, suggesting that this could be done by mixing some of the responsive southern mussels into the naïve northern stocks. "Although 15 years is fast to evolve better defenses to your predator, it can be painfully long if you're a shellfisherman," Byers adds.

This paper is one chapter of Freeman's doctoral dissertation, which also explores how mussels respond to sea stars and to multiple predators. He anticipates completing his doctoral work by October 2006, when he will begin a post-doctoral position with UNH research associate professor Fred Short.

Freeman notes that there's one predator mussels will not need to defend themselves against: him. "I used to like them, before I started working with them for my dissertation," he says. "Not anymore."

-30-


###
Editors and reporters: A photograph is available to download here: http://www.unh.edu/news/img/co.....rcinus.jpg

Caption: Scientists Aaren Freeman and James Byers at the University of New Hampshire (UNH) have found that invasive crab species Hemigrapsus sanguineus (left) and Carcinus maenas (right) may precipitate evolutionary change in blue mussels in as little as 15 years. Credit: Aaren Freeman.
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PostPosted: Mon Aug 21, 2006 6:20 am    Post subject: A new tool against brain disease Reply with quote

August 20, 2006
University of Utah

A new tool against brain disease
Snail toxin may spur new meds for Alzheimer's, Parkinson's, depression


University of Utah researchers isolated an unusual nerve toxin in an ocean-dwelling snail, and say its ability to glom onto the brain's nicotine receptors may be useful for designing new drugs to treat a variety of psychiatric and brain diseases.

"We discovered a new toxin from a venomous cone snail that may enable scientists to more effectively develop medications for a wide range of nervous system disorders including Parkinson's disease, Alzheimer's disease, depression, nicotine addiction and perhaps even schizophrenia," says J. Michael McIntosh.

Discovery of the new cone snail toxin will be published Friday, Aug. 25 in The Journal of Biological Chemistry by a team led by McIntosh, a University of Utah research professor of biology, professor and research director of psychiatry, member of the Center for Peptide Neuropharmacology and member of The Brain Institute.

McIntosh is the same University of Utah researcher who – as an incoming freshman student in 1979 – discovered another "conotoxin" that was developed into Prialt, a drug injected into fluid surrounding the spinal cord to treat severe pain due to cancer, AIDS, injury, failed back surgery and certain nervous system disorders. Prialt was approved in late 2004 in the United States and was introduced in Europe last month.

Prialt, sold by Ireland's Elan Pharmaceuticals, took roughly 25 years to reach market after its discovery in venom from the fish-eating cone snail Conus magus or magician's cone. McIntosh says he expects it will take 10 to 20 years to develop new medications based on what is learned from the new toxin – named alpha conotoxin OmIA (oh-em-one-ay) – isolated from a cone snail species named Conus omaria, which lives in the Pacific and Indian oceans and eats other snails. It ranges from 1¾ to 3½ inches long.

McIntosh discovered and analyzed the new toxin with help from University of Utah cone snail research pioneer Baldomero "Toto" Olivera, who is a distinguished professor of biology, and lab technicians Sean B. Christensen and Cheryl Dowell.

Other coauthors of the study are Palmer Taylor, professor and dean of pharmacology at the University of California, San Diego, and his associates – Todd Talley, Igor Tsigelny and Kwok-Yiu Ho – as well as Kyou-Hoon Han at the Korea Research Institute of Bioscience and Biotechnology.

Diseases that Might Benefit from the New Snail Toxin

McIntosh says the OmIA toxin will be useful in designing new medicines because it fits like a key into certain lock-like "nicotinic acetylcholine receptors" found on nerve cells in the brain and the rest of the nervous system.

"Those are the same types of receptors you activate if you smoke a cigarette," he says, explaining that nicotine in cigarette smoke "binds" to the receptor to trigger the release of a neurotransmitter, which is a chemical that carries a nerve impulse from one nerve cell to another, allowing nerve cells to communicate.

"Nicotine acts on those receptors in our brain, but they are in our brain for better reasons than to enjoy a cigarette," McIntosh says. Different forms or subtypes of nicotinic receptors control the release of different neurotransmitters. "That's important because if you had compounds to facilitate the release of one neurotransmitter and not another neurotransmitter, that opens up medicinal potential," he says.

"For instance, one receptor modifies the release of dopamine. There are inadequate amounts of dopamine in Parkinson's disease," so a medicine designed to fit into a certain subtype of nicotinic receptor would produce more dopamine and thus protect against the development of tremors and other Parkinson's symptoms. Indeed, other studies have found that smoking seems to forestall Parkinson's disease.

A medicine that could block certain nicotinic receptors could be used to help people stop smoking cigarettes, and the same method might work for alcoholism because nicotinic receptors may be involved in alcohol addiction, McIntosh says.

Other nicotinic receptors trigger the release of neurotransmitters involved in memory, so activating the right receptors might lessen Alzheimer's memory loss.

"One reason people smoke is they feel their thinking may be a little better, with increased attention and focus," McIntosh says, noting that pharmaceutical companies "would like to mimic that positive benefit without all the downsides of cigarette smoke."

Other nicotinic receptors influence "the release of serotonin and norepinephrine, two neurotransmitters strongly implicated in mood disorders" such as depression, so a drug to activate those receptors might treat depression, he adds.

Schizophrenics tend to smoke heavily because something in cigarette smoke "seems to help them filter out irrelevant stimuli. They can focus better," McIntosh says. So a drug aimed at certain nicotinic receptors might treat schizophrenia.

New Neurotoxin is a Key for Designing New Medicines

McIntosh says the new toxin itself is unlikely to become a drug because it blocks rather than stimulates nicotinic receptors. But because it can act on some types of nicotinic receptors and not others – like a key that opens some locks but not others – it has great potential as a tool for precisely identifying the shape and structure of the receptor "locks," thus making it easier to design new medicines or "keys" to fit those receptors and trigger them to release desired neurotransmitters.

In the new study, about 70 compounds from numerous cone snail species were screened in collaboration with Taylor's lab at the University of California, San Diego.

Taylor uses "acetylcholine binding protein" as a model for nicotinic receptors. In other words, cone snail toxin "keys" that fit into nicotinic receptor "locks" also fit into highly similar "locks" made of this binding protein. So the binding protein was used as a way to find toxins that also would fit into nicotinic receptors. The new OmIA toxin was most interesting because it tightly fits some nicotinic receptors but not others. A drug that tightly fits desired receptors but not others is less likely to have undesirable side effects.

Unlike nicotinic receptors, the binding protein can be grown in crystal form, allowing Taylor's team to use X-ray crystallography to make detailed microscopic pictures of how the toxin fit into the binding protein. Meanwhile, Han in South Korea used nuclear magnetic resonance to make pictures showing the structure of the new toxin.

Together, the images provide a highly detailed picture of how the cone snail toxin fits into the binding protein, and thus how it also would fit into a nicotinic receptor.

"By putting the two together, you can get a high-resolution picture of the binding site," says McIntosh. "That allows for rational drug development. It allows you to design compounds that will bind to the same [nicotinic receptor] site, and it allows you to begin to understand how to bind to one receptor subtype and not another" to trigger the release of whatever neurotransmitter is needed to treat or prevent a particular disease.

"It is the picture of the binding site and the ability to distinguish one type of nicotinic receptor from another that makes the toxin so valuable," he adds.

How the Study was Performed

The snails from which the new toxin was obtained were collected by divers in Olivera's native Philippines. Venomous snails use a dart-like tooth to zap fish, snails and other prey, injecting them with an immobilizing toxin. Venom from the collected snails was extracted at a lab in the Philippines, and then sent to Utah.

Once the screening process identified OmIA as promising, McIntosh and colleagues purified the toxin – one of perhaps 200 components in Conus omaria venom. They determined its chemical structure and then synthesized more of the toxin, since they had only a small amount of the natural version.

Next, the synthetic toxin was tested to see how well it acted as a "key" to fit into the "locks" represented both by binding proteins (from freshwater snails and a sea slug) and by actual nicotinic receptors, which came from rat cells but were grown in frog eggs. That allowed the researcher to grow various subtypes of the nicotinic receptors and see how well the toxin fit them.

Taylor and Han provided pictures of the physical structures of the binding protein "locks" and toxin "key," and then "used computer simulation to dock the two structures together," says McIntosh. "That generates a picture of the binding site – the points of contact between the toxin and the binding protein."

The site is the place a new drug would be designed to fit.

"The whole idea is to make the model of the nicotinic receptor so predictive that you can then really speed up the development of drugs," McIntosh says. "If you have an accurate model of the receptor, you can plug in a model of your drugs and do a lot of 'virtual screening.' Rather than synthesizing a million compounds and having all but one be duds, you can synthesize a few thousand compounds based on the model and come up with a better drug with less time and resources."


###
The Center for Peptide Neuropharmacology studies neurotransmitters and receptors that enable rapid information transfer in the brain. The Brain Institute includes more than 100 University of Utah scientists unlocking mysteries of the human brain via interdisciplinary collaboration. The institute supports scientists in turning research advances into technologies and treatments for brain disorders. See http://brain.utah.edu
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PostPosted: Wed Dec 13, 2006 1:44 pm    Post subject: Study finds oysters can take heat and heavy metals, but not Reply with quote

University of North Carolina at Charlotte
13 December 2006

Study finds oysters can take heat and heavy metals, but not both

Pollution is bad for the sea life and so is global warming, but aquatic organisms can be resilient. However, even organisms tough enough to survive one major onslaught may find that a double whammy is more than their molecular biology can take.

A new study has found that even relatively low levels of heavy metal pollution can interfere with the metabolic processes of oysters, and that the effects of the pollution become particularly notable when oyster metabolism is also affected by high seasonal temperatures. The combined effect is strong enough to lead to fatal weakness and disease, adding a fundamental explanation for documented oyster declines in the wild. The effect also reveals an additional impact that warming coastal waters may have on cold-blooded organisms.

Investigating the mechanisms by which the heavy metal cadmium and temperature can each affect metabolic processes in oysters, a new report by a team headed by University of North Carolina at Charlotte ecophysiologist Inna Sokolova finds that both cadmium and temperature independently decrease the efficiency of metabolic processes in the oysters’ mitochondria – the place where stored food is turned into the energy living cells run on.

The study also finds that cadmium can cause an increase in the production of reactive oxygen species – dangerous metabolic by-products – while higher temperatures hamper the cellular processes that normally prevent the compounds from causing damage. The findings will appear in the December issue of the Journal of Experimental Biology.

“We are studying a combination of factors,” said Sokolova. “Essentially what we are trying to look at is how oysters that live in metal-polluted environments respond to an increase in temperature, including normal seasonal increases in the summer, and global climate change, which will add to the problems they are already having in warm periods.”

Coming from human sources as diverse as cadmium-nickel batteries, yellow paint and mining, heavy metals like cadmium are common pollutants in estuaries where oysters live, Sokolova notes, but their concentrations occur at only few parts per billion – quantities long assumed to be too low to threaten marine life.

“We have looked at oysters’ metabolism, and have found out that their respiration rate increases when they are exposed to cadmium at environmentally relevant levels, as the organism spends more energy on basal maintenance,” Sokolova said.

“Metabolism also increases when they are exposed to higher temperatures. At some point, when they are exposed to both cadmium and higher temperatures, their metabolism can not go up any more and they start dying because they have hit the maximum level.”

In its native habitat on the east coast of North America, the eastern oyster lives in estuaries where the temperature ranges fluctuate seasonally -- from 0 to 4 degrees centigrade in the winter to temperatures as high as 35 degrees centigrade in the summer. According to Sokolova, past studies have shown that oysters stop growing at about 28 degrees centigrade, a temperature that can persist under normal summer conditions for several months in a row.

Through a series of studies examining the impact of cadmium concentrations and high temperatures at the environmental, organismal, cellular and biochemical levels, Sokolova and her team have narrowed the problem down to the effects of the two factors on a complicated series of chemical reactions that occur in the oysters’ mitochondria in the process of cellular metabolism.

The researchers found that cadmium affects mitochondrial function by reducing the efficiency of the metabolic cycle in producing adenosine triphosphate (ATP), the main molecule that cells use to transfer energy. The inefficiency is particularly pronounced as temperatures approach or exceed 30 degrees centigrade. The researchers suspected that the cadmium caused a malfunction in one of the stages of oxygen respiration resulting in the increased production of potentially cell-damaging compounds known as reactive oxygen species (ROS).

“We found that if you measure production of reactive oxygen species in the presence of cadmium, it is strongly increased,” Sokolova said. “Normally, the amount of oxygen that slips towards producing reactive oxygen is something like five percent in mollusks. When cadmium is present, then it is 30 percent,” she noted.

“In the presence of cadmium, mitochondria use nearly 30 percent of the oxygen that they consume to produce reactive oxygen species instead of using it for ATP synthesis.”

The research found that the cadmium-induced increase in ROS production does not harm oyster cells when the organisms are living in temperature conditions of 20 degrees centigrade or lower, as other chemical processes in the mitochondria are able to neutralize ROS under those conditions. However, at 30 degrees centigrade the researchers found that the cleanup processes cannot cope with ROS and oxidative damage occurs.

The team detected the effect by examining the metabolic enzyme aconitase, which is susceptible to damage from ROS. In the presence of cadmium and at 30 degrees centigrade, significant quantities of the enzyme were disabled, indicating oxidative damage.

“The degree of inactivation of aconitase can be used as a marker of how bad the oxidative damage is. We don’t really see a lot of oxidative damage at 20 degrees, even when we see a larger amount of reactive oxidative species being produced in the presence of cadmium. This means that the anti-oxidant systems are still adequate. But at 30 degrees the same concentrations of cadmium cause extensive oxidative damage and we see it in the inactivation of aconitase.”

According to Sokolova, the combined effects of temperature and heavy metal contamination on metabolic chemistry spell trouble for oysters and probably other cold blooded organisms as well. Though the levels of the pollutants have been determined to be tolerable, and oysters have evolved to be able to handle warm water temperatures for a few months, the combination pushes them to a crisis point where any further change (such as seasonal temperature increases caused by global warming) can make their survival unlikely.

“Oysters are right at the boundary already,” she said. “Some earlier studies show that oysters stop growing when the temperature is above 28 degrees. These conditions are stressful for them and they spend all their energy just staying alive – they don’t have anything extra that they can invest in growth. This also means that they don’t have anything extra that they can invest in protection against toxins that may be in the water. An increase in seasonal temperatures would be an additional problem.”

The current environmental stresses on oysters may in fact be partially responsible for recent outbreaks of disease that have already decimated many eastern oyster beds.

“Metabolic dysfunction can certainly contribute to disease susceptibility,” Sokolova noted. “A host-parasite relationship is always a two-sided story, and the outcome is dependent on the invasiveness and abundance of the parasite and the host's ability to ward the parasite off.

“Most immune functions are energy-dependent and quite expensive in energetic terms, so when energy demands for basal metabolic maintenance increase during temperature stress, less is left over for other functions such as immunity. On top of this, if the parasite can better and faster proliferate in the warmth, the balance can be tipped towards disease.”


###
Inna Sokolova’s research is funded in part by a National Science Foundation Career Award.

Source: Inna Sokolova, 704-687-8532
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PostPosted: Fri Dec 29, 2006 8:40 am    Post subject: Sea Slug Offers Clues to Human Brain Disorders Reply with quote

Sea Slug Offers Clues to Human Brain Disorders

By Jeanna Bryner
LiveScience Staff Writer
posted: 28 December 2006
12:26 pm ET

Beneath a slimy façade, the sea slug is somewhat of a brainiac.

At any given time within a single brain cell of this marine snail (Aplysia), more than 10,000 genes are hard at work, suggests a new study looking at aspects of the sea slug’s genome.

By probing the brain of Aplysia, researchers identified more than 100 genes similar to those associated with all major human neurological diseases and more than 600 genes controlling brain development.

The findings suggest that acts of learning or the progression of brain disorders do not take place in isolation, and instead stem from interactions between large clusters of genes within many cells.

For the full article:

http://www.livescience.com/ani.....slugs.html
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PostPosted: Wed Feb 28, 2007 8:17 am    Post subject: First Videos of Deep-Sea Squid Reveal Aggressive Predator Reply with quote

First Videos of Deep-Sea Squid Reveal Aggressive Predator

By Charles Q. Choi
Special to LiveScience
posted: 27 February 2007
11:34 am ET

The first live videos of the deep-sea eight-armed squid in its natural environment reveal it to be a fast, aggressive predator that flashes light shows potentially to blind prey or woo mates.

Zoologist Tsunemi Kubodera at Japan's National Science Museum in Tokyo and his colleagues, the same researchers who caught the first live giant squid (Architeuthis) footage two years ago, recorded the deep-sea eight-armed squid Taningia danae using a newly developed underwater high-definition video camera system.

For the full article and videos:

http://www.livescience.com/ani.....video.html
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PostPosted: Tue Apr 24, 2007 10:37 am    Post subject: Sea snails break the law Reply with quote

Smithsonian Tropical Research Institute
24 April 2007

Sea snails break the law

Scientists at the Smithsonian discover the re- evolution of a useful skill set
Lizards gave rise to legless snakes. Cave fishes don’t have eyeballs. In evolution, complicated structures often get lost. Dollo’s Law states that complicated structures can't be re-evolved because the genes that code for them were lost or have mutated. A group of sea snails breaks Dollo’s law, Rachel Collin, Staff Scientist at the Smithsonian Tropical Research Institute and colleagues from two Chilean universities announce in the April, 2007, Biological Bulletin.

"This is important because it shows that animals may carry the potential for evolutionary change around with them. When the environment changes, new life forms may be able to regain abilities that were lost earlier in evolutionary history," Collin explains.

Most species of sea snail go through several life stages on the way to becoming reproductive adults. The early stages, or larvae, usually live in the water column eating microscopic algae and swimming with a specialized structure called the velum. This stage has been lost in many species, where development happens in immobile capsules protected by the mother. In these species, small bottom-dwelling juvenile snails (miniature adults) hatch out of eggs and crawl away. Thus, a whole life stage, the motile larva, is lost and thought to never been re-gained.

But how can you tell what happened in the past to bring this about? Collaborators from Chile, Argentina and the Smithsonian in Panama, using embryological observations and DNA sequencing, show that the larval stage can be reacquired.

The group collected 6 species of the genus Crepipatella from the shorelines of Argentina, Chile, Panama, Peru, South Africa and the United States. They observed the developmental stages of each species and sequenced a gene called mitochondrial cytochrome oxidase I. Then, based on the differences in gene sequences, they used several different techniques to reconstruct family trees.

Indeed, they found that motile, feeding larvae had been lost and re-gained in the same family group, which breaks Dollo’s law. Collin sums this up: "The embryos of limpets in a group called Crepipatella seem to retain some of the apparatus they would need for larval feeding and swimming, even though they do not produce larvae. Then, from DNA data we see that one species with larvae has re-evolved in the middle of a group that doesn't have them. It does go both ways! There’s more flexibility in animal evolution than people thought."

###
The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.

Ref. Rachel Collin, Oscar Chaparro, Federico Winkler, and David Velez. 2007. It goes both ways: evidence that feeding larvae have been regained in a marine gastropod. Biological Bulletin. April, 2007.
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PostPosted: Tue May 01, 2007 8:04 am    Post subject: Why Do Oysters Choose to Live Where They Could be Eaten? Reply with quote

Why Do Oysters Choose to Live Where They Could be Eaten?

New research details oyster’s selection of home ties to future reproductive capacity
University of Maryland

Solomons, Md. (May 1, 2007) – There are many reasons why living in dense groups with others of your own kind is a good idea. Oftentimes, aggregations of a species serve as protection from predators and harsh environments or may be beneficial to future reproductive success. However, in the case of oyster larvae, the selection of a place to call home can be a life or death decision.

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http://www.umces.edu/oysterlarvae.html
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PostPosted: Sat Aug 11, 2007 7:26 am    Post subject: Slip Sliming Away Reply with quote

Slip Sliming Away
Emily Sohn

Aug. 8, 2007

Slugs and snails produce slime that looks a lot like the stuff that comes out of your nose. These creatures don't use tissues to wipe up their snot, though. Instead, they use the goo to help them stick to surfaces and crawl over obstacles.

For years, scientists have been studying slug slime to better understand what it's made of and how it works. Recently, researchers at the Massachusetts Institute of Technology (MIT) in Cambridge created a robotic slug that crawls on slime, just like real slugs do.

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http://www.sciencenewsforkids......ature1.asp
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PostPosted: Fri Sep 14, 2007 2:12 pm    Post subject: Mussels Disappear from Streams and Dinner Plates Reply with quote

Mussels Disappear from Streams and Dinner Plates
By Andrea Thompson, LiveScience Staff Writer

posted: 14 September 2007 09:53 am ET

Mussels may start disappearing from restaurant menus as species increasingly become extinct or endangered by human activities, scientists say.

North America has historically had a very diverse community of freshwater mussels—providing ample supplies for diners. But populations have been on the decline for the past few decades, and mussels now are one of the most endangered groups of animals on the continent, according to the U.S. Fish and Wildlife Service

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http://www.livescience.com/ani.....cline.html
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PostPosted: Sat Oct 27, 2007 6:26 am    Post subject: Acid Snails Reply with quote

Acid Snails
Emily Sohn

Oct. 24, 2007

Conditions in the world's oceans are changing, thanks to human activities. And those changes might be affecting the ability of a small snail to defend itself, suggests a new study.
Factories, cars, and other machines spit out lots of a gas called carbon dioxide. Carbon dioxide (CO2) is known as a greenhouse gas because it traps heat in the atmosphere. More and more of the gas has been accumulating in the air in recent years.

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http://www.sciencenewsforkids....../Note3.asp
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PostPosted: Mon May 05, 2008 1:13 pm    Post subject: Squid beak balances hard and soft Reply with quote

Squid beak balances hard and soft
By Jenny Cutraro
May 2nd, 2008
Yet, the squishy creature’s bite packs a lot of punch

A squishy squid has some chemical tricks that help it hold on to its tough, rigid beak without hurting itself.

Squids look soft and squishy — and for the most part, they are. Yet a squid's beak — the rigid part of its mouth — is hard enough to snap a fish's spine with just one bite.

For the full article:

http://sciencenews.org/view/ge.....d_and_soft
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