Metabolically Engineered Bacteria

Science (July 27, 2010) — Researchers have long envied spiders’ ability to manufacture silk that is light-weighted while as strong and tough as steel or Kevlar. Indeed, finer than human hair, five times stronger by weight than steel, and three times tougher than the top quality man-made fiber Kevlar, spider dragline silk is an ideal material for numerous applications. Suggested industrial applications have ranged from parachute cords and protective clothing to composite materials in aircrafts. Also, many biomedical applications are envisioned due to its biocompatibility and biodegradability.

Unfortunately, natural dragline silk cannot be conveniently obtained by farming spiders because they are highly territorial and aggressive. To develop a more sustainable process, can scientists mass-produce artificial silk while maintaining the amazing properties of native silk? That is something Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the Republic of Korea, and his collaborators, Professor Young Hwan Park at Seoul National University and Professor David Kaplan at Tufts University, wanted to figure out. Their method is very similar to what spiders essentially do: first, expression of recombinant silk proteins; second, making the soluble silk proteins into water-insoluble fibers through spinning.

For the successful expression of high molecular weight spider silk protein, Professor Lee and his colleagues pieced together the silk gene from chemically synthesized oligonucleotides, and then inserted it into the expression host (in this case, an industrially safe bacterium Escherichia coli which is normally found in our gut). Initially, the bacterium refused to the challenging task of producing high molecular weight spider silk protein due to the unique characteristics of the protein, such as extremely large size, repetitive nature of the protein structure, and biased abundance of a particular amino acid glycine. “To make E. coli synthesize this ultra high molecular weight (as big as 285 kilodalton) spider silk protein having highly repetitive amino acid sequence, we helped E. coli overcome the difficulties by systems metabolic engineering,” says Sang Yup Lee, Distinguished Professor of KAIST, who led this project. His team boosted the pool of glycyl-tRNA, the major building block of spider silk protein synthesis. “We could obtain appreciable expression of the 285 kilodalton spider silk protein, which is the largest recombinant silk protein ever produced in E. coli. That was really incredible.” says Dr. Xia.

But this was only step one. The KAIST team performed high-cell-density cultures for mass production of the recombinant spider silk protein. Then, the team developed a simple, easy to scale-up purification process for the recombinant spider silk protein. The purified spider silk protein could be spun into beautiful silk fiber. To study the mechanical properties of the artificial spider silk, the researchers determined tenacity, elongation, and Young’s modulus, the three critical mechanical parameters that represent a fiber’s strength, extensibility, and stiffness. Importantly, the artificial fiber displayed the tenacity, elongation, and Young’s modulus of 508 MPa, 15%, and 21 GPa, respectively, which are comparable to those of the native spider silk.

“We have offered an overall platform for mass production of native-like spider dragline silk. This platform would enable us to have broader industrial and biomedical applications for spider silk. Moreover, many other silk-like biomaterials such as elastin, collagen, byssus, resilin, and other repetitive proteins have similar features to spider silk protein. Thus, our platform should also be useful for their efficient bio-based production and applications,” concludes Professor Lee.

This work is published on July 26 in the Proceedings of the National Academy of Sciences (PNAS) online

Sourced & published by Henry Sapiecha

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.

“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

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

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.

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.

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

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

• Age: 62
• Gender: Male
• Astrological Sign: Libra
• Zodiac Year: Boar
• Industry: Technology
• Occupation: Inventor
• Location: Hervey Bay : Qld : Australia

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

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

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

Stay Slim and Healthy

on a High-Fat Diet

On Butterfly Wings

Inspire More Powerful Solar Cells

Materials Engineers Turn to Ferocious

Fish for Nonstick Ship Coating