Sharks Can Really Sniff out Their Prey,

and This Is How They Do It

Science (June 10, 2010) — It’s no secret that sharks have a keen sense of smell and a remarkable ability to follow their noses through the ocean, right to their next meal. Now, researchers reporting online on June 10th in Current Biology, have figured out how the sharks manage to keep themselves on course.

It turns out that sharks can detect small delays, no more than half a second long, in the time that odors reach one nostril versus the other, the researchers report. When the animals experience such a lag, they will turn toward whichever side picked up the scent first.

“The narrow sub-second time window in which this bilateral detection causes the turn response corresponds well with the swimming speed and odor patch dispersal physics of our shark species,” known as Mustelus canis or the smooth dogfish, said Jayne Gardiner of the University of South Florida. All in all, it means that sharks pick up on a combination of directional cues, based on both odor and flow, to keep themselves oriented and ultimately find what they are looking for.

If a shark experiences no delay in scent detection or a delay that lasts too long — a full second or more — they are just as likely to make a left-hand turn as they are to make a right.

These results refute the popular notion that sharks and other animals follow scent trails based on differences in the concentration of odor molecules hitting one nostril versus the other. It seems that theory doesn’t hold water when one considers the physics of the problem.

“There is a very pervasive idea that animals use concentration to orient to odors,” Gardiner said. “Most creatures come equipped with two odor sensors — nostrils or antennae, for example — and it has long been believed that they compare the concentration at each sensor and then turn towards the side receiving the strongest signal. But when odors are dispersed by flowing air or water, this dispersal is incredibly chaotic.”

Indeed, Gardiner explained, recent studies have shown that concentrations of scent molecules could easily mislead. Using dyes that light up under laser light, scientists found that there can be sudden peaks in the concentrations of molecules even at a distance from their source.

Gardiner’s team suggests that the findings in the small shark species they studied may help to explain the evolution of the wide and flat heads that make hammerhead sharks so recognizable. One idea has held that the characteristic hammerhead may lend the animals a better sense of smell. But studies hadn’t shown their noses to be all that remarkable, really. For instance, they don’t respond to odors at concentrations lower than other sharks. The new findings suggest that the distance between their nostrils could be the key.

“If you consider an animal encountering an odor patch at a given angle, an animal with more widely spaced nostrils will have a greater time lag between the odor hitting the left and right nostrils than an animal with more closely spaced nostrils,” Gardiner said. “Hammerheads may be able to orient to patches at a smaller angle of attack, potentially giving them better olfactory capabilities than pointy-nosed sharks.” That’s a theory that now deserves further testing.

In addition to giving insights into the evolution and behavior of sharks, the findings might also lead to underwater robots that are better equipped to find the source of chemical leaks, like the oil spill that is now plaguing the Gulf Coast, according to the researchers.

“This discovery can be applied to underwater steering algorithms,” Gardiner said. “Previous robots were programmed to track odors by comparing odor concentrations, and they failed to function as well or as quickly as live animals. With this new steering algorithm, we may be able to improve the design of these odor-guided robots. With the oil spill in the Gulf of Mexico, the main oil slick is easily visible and the primary sources were easy to find, but there could be other, smaller sources of leaks that have yet to be discovered. An odor-guided robot would be an asset for these types of situations.”

The researchers include Jayne M. Gardiner, University of South Florida, Tampa, FL, Center for Shark Research, Mote Marine Laboratory, Sarasota, FL; and Jelle Atema, Boston University Marine Program, Boston, MA, Marine Biological Laboratory, Woods Hole, MA, Woods Hole Oceanographic Institution, Woods Hole, MA.

Sourced and published by Henry Sapiecha 11th June 2010

Climate change killing lizards worldwide


SANTA CRUZ, Calif. (UPI) — Twenty percent of all lizard species could be extinct by 2080 because of rising temperatures involved in climate change, a California researcher said.

Lizards worldwide are far more susceptible to climate-warming extinction than previously thought because many species already live at the edge of their thermal limits, said Barry Sinervo of the Department of Ecology and Evolutionary Biology at the University of California, Santa Cruz.

Sinervo and colleagues from around the world said they reached their conclusions after comparing field studies of lizards in Mexico to lizard studies from other countries.

Rising temperatures already have driven an estimated 12 percent of Mexico’s Sceloporus lizard population to extinction, the scientists wrote in a recent issue of the journal Science.

“We are actually seeing lowland species moving upward in elevation, slowly driving upland species extinct, and if the upland species can’t evolve fast enough then they’re going to continue to go extinct,” Sinervo said in a release from the university Thursday.

Sourced and published by Henry Sapiecha 7th June 2010

Clam Cleanup

Biologists Clam Up Waterways

To Determine Sources Of Pollution

January 1, 2009 — Biologists are able to determine the sources of toxins in water by using clams as pollutant traps. Clams naturally clean water by feeding absorbing toxins in their tissues as they draw in water. By placing the clams downstream of industrial parks and highways, they can be analyzed for pollutants. Biologists open the clams after exposure to these waters and detach them from their shells– various lab tests reveal contaminants in the waterway.

See also:
Plants & Animals

Many of our streams and rivers are contaminated with pollutants like pesticides, lead, arsenic and PCBs. It’s a problem that’s costly to clean up. Scientists are using a new, inexpensive way to fix the problem.

Lurking in many rivers and streams are contaminants. Some you can see, and some you can’t. Hidden chemicals ruin waterways and everything in it. To clean things up, biologists are teaming up with local high school students to dredge up clams to use as tiny detectives. They help by finding the source of toxic leaks.

“We’re using them as pollutant traps,” said Harriette Phelps, Ph.D., a biologist at the University of the District of Columbia in Washington, D.C.

Students put the clams in streams that lead to rivers. Clams then suck in water swept down from industrial parks and highways.

“It’s been a great experience to actually come and see them and be the ones to pick them up out of the water,” student Caitlin Virta said.

Clams clean the water as they feed, absorbing toxins in their tissues. The clams are collected back from streams. Then, scientists pry open the clams and detach them from their shell. Later, lab tests reveals the clam’s secret — the kinds and quantities of pollutants in the water.

“We can trace them back to sources, and then hopefully we can go from there and get rid of the sources,” Dr. Phelps said.

The clams detected a banned pesticide in Maryland, believed buried years ago and now slowly leaking. “I thought it was really cool how you could tell the health of a stream from analyzing clam leftovers,” Virta said.

It’s a cool way to clean up the environment.

BIOACCUMULATION AND CLAMS: Clams are filter-feeders, meaning they draw water into their shells, remove the food they find, and then draw in more food-rich water to continue feeding. This means that lots of water works its way through their shells. The muscle of the clam gathers not only food, but other material suspended in water during this process, which can lead to the accumulation of toxins and pollutants. Bioaccumulation is the term for toxins and pollutants that collect in the tissue of an organism. Biomagnification is a related term, referring to the transfer of such substances from prey to predator. If a prey animal bioaccumulates toxins in its body, then its predator, after consuming many of the smaller animals will accumulate many, many times the amount of the toxin in any one of their prey.

SECONDARY STANDARDS: Even if your tap water meets the EPA’s basic requirement for safe drinking water, some people still object to the taste, smell or appearance of their water. These are aesthetic concerns, however, and therefore fall under the EPA’s voluntary secondary standards. Some tap water is drinkable, but may be temporarily clouded because of air bubbles, or have a chlorine taste. A bleach-like taste can be improved by letting the water stand exposed to the air for a while.

The American Geophysical Union contributed to the information

Sourced and published by Henry Sapiecha 7th June 2010


SEX IN THE OCEAN IS GREAT FOR THESE OYSTERS

NEWLY INVENTED OYSTER BEDS ON WHICH OYSTERS GROW

BRING A NEW MEANING TO THE TERM ‘SEA BED’


Hi, this is Rex Ellis.

I am thrilled because my Harvest Post has now reached production stage! I have been developing this idea since 2006 and have had  great feed back and a lot of encouragement by the industry.
Have a look at the post with the baskets in the pic  and see for yourself. Today we have been out to sea and have sank the post within seconds into the sea bed. It was indeed very difficult to remove it again. The harvest post is very strong and can carry multiple baskets with single compartments in order to grow shellfish stress free and in a shorter time than so far possible thanks to 48 single compartments per basket.

I am ready to take your orders, please contact me for a quote on a custom made solution for your needs.

THE PRODUCT IS GUARANTEED TO HAVE A LIFE OF AT LEAST 25YEARS

…………………………………………………………………………………………………………………….

HARVEST POST INVENTOR

[OYSTER GROWING]

Rex Ellis

About Me

I have worked in the plastic industry for over 20 years. We developed different products like tanks and a plastic picket fence with an inbuilt watering system. The idea about the revolutionising way of growing shellfish came to me when I saw how labour intensive and physically demanding the growing of shellfish is. Because I love eating oysters, scallops and mussels myself I want to see the highest quality of shellfish grown especially in New Zealand, my home country and Australia, my chosen place to live

0407 820 030
rexellisharvestpost@gmail.com

Sourced and published by Henry Sapiecha 4th May 2010

Scientists Uncover

Transfer of Genetic Material

Between Blood-Sucking Insect

and Mammals

Science(Apr. 30, 2010) — Researchers at The University of Texas at Arlington have found the first solid evidence of horizontal DNA transfer, the movement of genetic material among non-mating species, between parasitic invertebrates and some of their vertebrate hosts.

The findings are published in the April 28 issue of the journal Nature, one of the world’s foremost scientific journals.

Genome biologist Cédric Feschotte and postdoctoral researchers Clément Gilbert and Sarah Schaack found evidence of horizontal transfer of transposon from a South American blood-sucking bug and a pond snail to their hosts. A transposon is a segment of DNA that can replicate itself and move around to different positions within the genome. Transposons can cause mutations, change the amount of DNA in the cell and dramatically influence the structure and function of the genomes where they reside.

“Since these bugs frequently feed on humans, it is conceivable that bugs and humans may have exchanged DNA through the mechanism we uncovered. Detecting recent transfers to humans would require examining people that have been exposed to the bugs for thousands of years, such as native South American populations,” Feschotte said.

Data on the insect and the snail provide strong evidence for the previously hypothesized role of host-parasite interactions in facilitating horizontal transfer of genetic material. Additionally, the large amount of DNA generated by the horizontally transferred transposons supports the idea that the exchange of genetic material between hosts and parasites influences their genomic evolution.

“It’s not a smoking gun, but it is as close to it as you can get,” Feschotte said

The infected blood-sucking triatomine, causes Chagas disease by passing trypanosomes (parasitic protozoa) to its host. Researchers found the bug shared transposon DNA with some hosts, namely the opossum and the squirrel monkey. The transposons found in the insect are 98 percent identical to those of its mammal hosts.

The researchers also identified members of what Feschotte calls space invader transposons in the genome of Lymnaea stagnalis, a pond snail that acts as an intermediate host for trematode worms, a parasite to a wide range of mammals.

The long-held theory is that mammals obtain genes vertically, or handed down from parents to offspring. Bacteria receive their genes vertically and also horizontally, passed from one unrelated individual to another or even between different species. Such lateral gene transfers are frequent in bacteria and essential for rapid adaptation to environmental and physiological challenges, such as exposure to antibiotics.

Until recently, it was not known horizontal transfer could propel the evolution of complex multicellular organisms like mammals. In 2008, Feschotte and his colleagues published the first unequivocal evidence of horizontal DNA transfer.

Millions of years ago, tranposons jumped sideways into several mammalian species. The transposon integrated itself into the chromosomes of germ cells, ensuring it would be passed onto future generations. Thus, parts of those mammals’ DNA did not descend from their common ancestors, but were acquired laterally from another species.

The actual means by which transposons can spread across widely diverse species has remained a mystery.

“When you are trying to understand something that occurred over thousands or millions of years ago, it is not possible to set up a laboratory experiment to replicate what happened in nature,” Feschotte said.

Instead, the researchers made their discovery using computer programs designed to compare the distribution of mobile genetic elements among the 102 animals for which entire genome sequences are currently available. Paul J. Brindley of George Washington University Medical Center in Washington, D.C., contributed tissues and DNA used to confirm experimentally the computational predictions of Feschotte’s team.

When the human genome was sequenced a decade ago, researchers found that nearly half of the human genome is derived from transposons, so this new knowledge has important ramifications for understanding the genetics of humans and other mammals.

Feschotte’s research is representative of the cutting edge research that is propelling UT Arlington on its mission of becoming a nationally recognized research institution.

Sourced and published by Henry Sapiecha 2nd May 2010

Chinese Pigs ‘Direct Descendants’ of

First Domesticated Breeds

ScienceDaily (Apr. 20, 2010) — Modern-day Chinese pigs are directly descended from ancient pigs which were the first to be domesticated in the region 10,000 years ago, a new archaeological and genetic study has revealed.

An international team of researchers, led by Durham University (UK) and the China Agricultural University, in Beijing, say their findings suggest a difference between patterns of early domestication and movement of pigs in Europe and parts of East Asia.

The research, published April 19 in the Proceedings of the National Academy of Sciences USA, looked at the DNA sequences of more than 1,500 modern and 18 ancient pigs.

Lead author Dr Greger Larson, in the Department of Archaeology, at Durham University, said: “Previous studies of European domestic pigs demonstrated that the first pigs in Europe were imported from the Near East. Those first populations were then completely replaced by pigs descended from European wild boar.

“However, despite the occurrence of genetically distinct populations of wild boar throughout modern China, these populations have not been incorporated into domestic stocks.

“The earliest known Chinese domestic pigs have a direct connection with modern Chinese breeds, suggesting a long, unbroken history of pigs and people in this part of East Asia.”

The finding is part of a wider research project into pig domestication and early human migration in East Asia.

The study also uncovered multiple centres of pig domestication and a complex picture of human migration across East Asia.

After pigs were incorporated into domestic stocks in Southeast Asia, the animals then migrated with people south and east to New Guinea, eventually reaching the remote Pacific, including Hawai’i, Tahiti, and Fiji, the researchers said.

The DNA analysis also found that wild boar were probably domesticated in many places including India and peninsular Southeast Asia several thousand years ago.

As current interpretations of archaeological records in these regions do not yet support these findings, the group has referred to them as “cryptic domestications.”

They suggest that additional archaeological digs and new analytical techniques may help to resolve the problem.

Dr Larson added: “Our evidence suggests an intriguingly complex pattern of local domestication and regional turnover and calls for a reappraisal of the archaeological record across South and East Asia.

“We may even find additional centres of pig domestication when we take a closer look at the picture in that part of the world.”

The research is part of an ongoing research project based at Durham University which aims to re-evaluate the archaeological evidence for pig domestication and husbandry and explore the role of animals in reconstructing ancient human migration, trade and exchange networks.

The DNA testing was carried out at the China Agricultural University and was analysed at Durham University and Uppsala University, Sweden.

The research was funded by the National Basic Research Programme of China and the National Key Technology R&D Programme of China.

Sourced and published by Henry Sapiecha 21st April 2010

High-Altitude Metabolism Lets Mice

Stay Slim and Healthy

on a High-Fat Diet

ScienceDaily (Apr. 16, 2010) — Mice that are missing a protein involved in the response to low oxygen stay lean and healthy, even on a high-fat diet, a new study has found.

“They process fat differently,” said Randall Johnson, professor of biology at the University of California, San Diego, who directed the research, which is published in the April 15 issue of the journal Cell Metabolism. While their normal littermates gain weight, develop fatty livers and become resistant to insulin on a high fat diet, just like overweight humans do, the mutant mice suffered none of these ill effects.

The protein, an enzyme called FIH, plays a key role in the physiological response to low levels of oxygen and could be a new target for drugs to help people who struggle with weight gain. “The enzyme is easily inhibited by drugs,” Johnson said.

Because the protein influences a wide range of genes involved in development, the scientists were surprised that its deletion improved health.

“We expected them to die as embryos,” said Na Zhang, a graduate student in Johnson’s lab and lead author of the study. “Then we saw they can survive for a long time.”

“From the beginning I noticed that these mice are smaller, but not sick. These mice seem to be healthy,” Zhang said. The lean mice have a high metabolism, and a common check for insulin resistance, a symptom of diabetes, revealed a super sensitivity to insulin.

“We fed the mice with a very high fat diet — 60 percent fat — just to see how they would respond,” Zhang said. “Mutants can eat a lot, but they didn’t gain a lot of weight. They are less fatty around their middles compared with their littermates.”

Obese people develop a “fatty liver,” and so did the wild type littermates. The fat mice also developed high blood cholesterol with elevated levels of the “bad” type, LDL. In lean mutants, LDL increased much less.

“All of these observations support that the modified mice have better metabolic profiles,” Zhang said.

The genetic manipulations disabled the FIH gene entirely. “In every tissue, in every cell, the protein is gone,” Zhang said. But the scientists wanted to know what part of the mouse physiology was responsible for the changes, so they created new mice in which the FIH protein was deleted only in specific tissues: the nervous system or the liver.

Mice that were missing FIH only from their nervous system showed most of the same effects. “But if it was only deleted in the liver, then no.” Zhang said.

Though smaller, the mutant mice eat and drink 30 to 40 percent more than wild-type mice.

“Where do those calories go? To heat generation and an increased heart rate.” Johnson said. They also breathe heavily compared with normal mice, taking in 20 to 40% more air. “This deep breathing is like exercise for them.”

The FIH protein is part of a wide system that responds to low levels of oxygen. The mice behave as if they are breathing thin air. When people travel to higher altitudes, they breathe heavily for a few days, then adjust by producing more oxygen-carrying blood cells. “These mice never adjust to the apparent low oxygen,” Johnson said. “They stay in this acute phase of hypoxic response their whole lives.”

Sourced and published by Henry Sapiecha 19th April 2010

Natural Solar Collectors

On Butterfly Wings

Inspire More Powerful Solar Cells

ScienceDaily (Feb. 5, 2009) — The discovery that butterfly wings have scales that act as tiny solar collectors has led scientists in China and Japan to design a more efficient solar cell that could be used for powering homes, businesses, and other applications in the future.

In the study, Di Zhang and colleagues note that scientists are searching for new materials to improve light-harvesting in so-called dye-sensitized solar cells, also known as Grätzel cells for inventor Michael Grätzel. These cells have the highest light-conversion efficiencies among all solar cells — as high as 10 percent.

The researchers turned to the microscopic solar scales on butterfly wings in their search for improvements. Using natural butterfly wings as a mold or template, they made copies of the solar collectors and transferred those light-harvesting structures to Grätzel cells. Laboratory tests showed that the butterfly wing solar collector absorbed light more efficiently than conventional dye-sensitized cells. The fabrication process is simpler and faster than other methods, and could be used to manufacture other commercially valuable devices, the researchers say.

Sourced and published by Henry Sapiecha 15th April 2010

Shark-Inspired Boat Surface

Materials Engineers Turn to Ferocious

Fish for Nonstick Ship Coating

May 1, 2005 — Researchers are using shark skin as a model for creating new coatings that prevent adhesion of algae and barnacles to boats. The new coating is modeled after sharks’ placoid scales, which have a rectangular base embedded in the skin with tiny spines or bristles that poke up from the surface that prevent things from attaching to the shark’s skin.

GAINESVILLE, Fla.–In the boating industry, a huge problem exists that can be summed up in three words — algae, barnacles and slime. Until now, the only way to prevent these organisms from growing was toxic paint. But researchers are studying a more natural approach that’s inspired by the ocean’s fiercest predator.

In movies, they’re the enemy, but in the world of science, sharks are allies.

Materials engineer Tony Brennan, of University of Florida in Gainesville, uses shark skin as a model for creating new surfaces. “The shark scales have a roughness that approximates the roughness that we had predicted would be a good roughness to stop adhesion,” he says.

Brennan designed the surfaces to prevent algae and barnacles from growing on boats. He says, “We started making surfaces that are mimicking the shark’s skin.”

A computer program helped researchers create the pattern and structure…

“Whatever we can draw, we can make into a surface,” says UF graduate student, Jim Schumacher.

And just like shark skin, spores can’t fit in the ridges and don’t want to balance on top of the surface Brennan and his team designed in the lab. “That’s a tremendous benefit to energy consumption, dollars and maintenance,” Brennan says.

Getting rid of those barnacles and other organisms would mean less cleaning and not having to drag around the extra weight would lower fuel costs.

“If it’s effective, it would tremendously affect the industry,” Emerson says.

When the surface hits the market in the next year, it could impact private boaters and Navy vessels, too. Researchers are also studying the shark-coated surface for medical applications.

In addition to being very thick — as much as four inches in some species — shark skin is made up of tiny rectangular scales topped with even smaller spines or bristles, making the skin rough to the touch.

Shark skin was used in the past as an abrasive, for polishing wood. In Asia, it was used to decorate sword hilts. In the South Pacific, natives used it for the membranes on drums. Even today, because shark skin is so tough and pliable, it is used to make fine leather goods, including purses, shoes, boots and wallets.

Shark skin is covered with tiny scales, known as placoid scales. These scales resemble small shark teeth in both appearance and structure: there is an outer layer of enamel, dentine, and a central pulp cavity. (Biologists call them “dermal denticles,” which literally translates into “tiny skin teeth.”)

Sharks essentially have a built-in suit of chain mail armor that doesn’t make them too stiff to move. The scales move and flex as the shark swims.

The shark skin’s dentine layer is made of a hard, crystalline material, which is embedded in a soft protein. This is important because embedding a hard material inside a softer one combines the best properties of both: a material that is rigid without being brittle.

The structure of shark skin has another function besides protection. The streamlined shape of the scales decreases the friction of the water flowing along the shark’s body by channeling it through grooves. The grooves are so closely spaced, they prevent eddies from coming into contact with the surface of the shark’s moving body. This reduces the amount of “drag” as the shark swims, enabling the creature to glide farther on a given amount of energy. Scientists have found that the ridges created by shark scales can reduce drag in the water by as much as 8 percent. Golf balls and many military aircraft and vessels employ similar drag-reducing principles.

Sourced and published by Henry Sapiecha 9th April 2010

Rats found to mentally re-enact events

TRAIN YOUR RAT

look_im_a_star_mouse Rat thinks its a star

CAMBRIDGE, Mass. (UPI) — U.S. scientists say they have discovered rats engage in a mental re-enactment of their recent experiences when choosing what actions to take.

Massachusetts Institute of Technology researchers said they recorded the activity of single neurons called “place cells” in a brain structure — the hippocampus — that has been shown to be crucial for learning and memory. They found place cells are activated in a unique pattern and sequence for each specific location in a maze.

When examining the brain recordings, the scientists determined the same pattern and sequence of activation took place during pauses in activity, and when rats confronted a choice of routes in the maze. The researchers found while a rat is awake but standing still in the maze, its neurons fire in the same pattern of activity that occurred while it was running.

“This may be the rat equivalent of ‘thinking,’” said Professor Matthew Wilson, who led the study. “This thinking process looks very much like the reactivation of memory that we see during non-REM dream states, consisting of bursts of time-compressed memory sequences lasting a fraction of a second. So thinking and dreaming may share the same memory reactivation mechanisms.”

The researchers, who included Fabian Kloosterman and Thomas Davidson, say their findings might also reflect how memory systems fail in people with Alzheimer’s disease and schizophrenia.

brain-xray-1

The study appears in the journal Neuron.

Copyright 2009 by United Press Internationa

Sourced and published by Henry Sapiecha 8th Sept 2009

flashing-bright-blue-line

Previous Entries Next Entries