Sth America's oldest predator fossil found

Palaeontologists say they have found the fossil of a carnivorous predator that lived more than 260 million years ago and is the oldest unearthed in South America.

"This predator lived nearly 40 million years before the dinosaur and is a precursor to mammifers," said Juan Carlos Cisneros, of the Federal University of Piaui.

The fossil, a complete 35-centimetre skull found in 2008 in the southern Brazilian state of Rio Grande do Sul, was restored and analysed by South African and Turkish experts who validated the discovery and published it inProceedings of the National Academy of Sciences.

"We are talking about the oldest fossil ever found in South America of a species of the last period of the Palaeozoic era - before the separation of the continents, with characteristics of species only known in South Africa and Russia," says Cisneros.

The remains found are those of a species of dinocephalus, a remote relative of mammifers.

The discovery made it possible to reconstruct the body of the predator believed to have been three meters long and to have weighed 300 kilograms.

It had four big hook-shaped canine teeth (two upper and two lowers) to catch its prey as well as other saw-shaped teeth, says Cisneros.

The species may have walked from South Africa to South America but the long distance to Russia, where similar species have also been found, raises questions as to the shape of the single continent which then made up the world to allow the movement these animals, he added.

The dinocephalus became extinct 250 million years ago along with 90 per cent of species on the planet as a result of volcanic explosions.

(The fossilized skull was found in 2008 on a farm in the Pampas Region of Rio Grande do Sul) 

Devastating blood fluke's code cracked

Scientists have unravelled the genetic code of the blood parasite that causes an insidious tropical disease linked to bladder cancer and HIV/AIDS in Africa.

The international team, led by Dr Neil Young from theUniversity of Melbourne, sequenced the genome ofSchistomosma haematobium.

Their work, which is published this week in Nature Genetics, also identifies possible targets for the development of drugs and vaccines for schistosomiasis, also known as bilharzia or swimmer's itch.

Schistosomiasis is spread to humans from small larvae shed from freshwater snails. The larvae burrows into the skin and travels through body to eventually develop as adult worms in blood vessels surrounding either the intestines or the bladder and genital tract, where they breed and cause chronic infection.

Of the three main species of parasite that cause schistosomiasis, Schistomosma haemotobium causes the most devastating form, says Young.

Affecting around 112 million people in Africa,Schistomosma haematobium causes chronic urogenital tract disease and is linked to bladder cancer and susceptibility to HIV/AIDS.

The two other major species — S. mansoni which is found in South America and Africa, and S. japonicum, which is found in China, cause intestinal and liver disease.

"While the intestinal form of the disease, which is caused by S. japonica and S. mansoni is important, S. haematobium causes more than half the infections in Africa," says Young.

There is currently no vaccine and only one drug available to treat S. haematobuim infections.

Young says most of the research into the disease is based around S. mansoni which was mapped three years ago along with S. japonica.

"Having genomic maps for all three species is essential," he says.

"When you're searching for drugs and vaccine targets you have to know that they are going to treat the majority of infections," he says.

But until now, research into this species has been "put in the too hard basket" because the species' host snails don't take well to laboratory life.

Using single cell sequencing, the team extracted the nuclear genome from a single pair of worms by amplifying DNA taken out of a single cell.

"That's a tremendous breakthrough because it means we don't have to grow the animals in the lab," says Young.

Proving the technique works makes genetic sequencing more effective and opens the way for studying other types of neglected parasitic diseases, says Young.

(Swimmer's Itch: Schistosomiasis or bilharzia is transmitted to humans via contact with contaminated water) 

Target proteins

Their analysis of the genome reveals that S. haemotobium has a similar number of genes and genetic structure to the other two species, but is most closely related to S. mansoni.

Young says the research will help scientists identify common proteins that can be knocked out or targeted with new or even existing drugs.

"For the first time we can start to look at the similarities from a drug and vaccine perspective and it will be interesting to see what biological differences there are between these species," he says.

By comparing the genome to the other two species and model species such as roundworms (C. elegans), fruit flies and mice the researchers identified six molecules as possible prime targets for drugs that may be effective against all species of the fluke.

He says the group's research will also allow scientists to hone in on other species of flatworms — a distinct evolutionary group closely related to molluscs — which cause human and animal diseases.

Their analysis identifies thousands of common proteins found in other types of flatworms such as liver flukes that infect cattle.

The genome sequence is publicly available in a database that also contains the blueprints of the other two species.

"We wanted to make it a comparative resource, rather than have one genome in one place and another genome in another," says Young.

Mineral quashes deadly bacterial poisons

A simple mineral supplement — manganese — holds promise as the first successful treatment for hemorrhage-inducing infections caused by some food- and waterborne germs. The mineral helps detoxify Shiga toxin, which is produced by a host of bacteria, including the type of E. coli that killed scores and sickened more than 3,700 people in Europe last year.

The new work, by researchers at Carnegie Mellon University in Pittsburgh, appears in the Jan. 20 Science.

Although the data are preliminary, “it’s an exciting finding,” says microbiologist Vernon Tesh of the Texas A&M Health Science Center in Bryan, who did not participate in the new study. Manganese might soon offer a low-cost treatment that physicians could administer “to every patient that comes into the clinic with a bloody stool,” he says.

“That would be a tremendous boon,” he adds, because although antibiotics can wipe out germs responsible for these infections, such drugs are strongly discouraged. Killing the bugs only expedites their release of Shiga toxin, increasing a patient’s risk of kidney failure, stroke and death.

The new finding “is a classic example of serendipity in science,” says coauthor Adam Linstedt, a cell biologist at Carnegie Mellon. His team has been exploring the somewhat mysterious cellular role of a protein called GPP130. Then a colleague at the University of California, Santa Cruz reported the puzzling observation that giving cells manganese made their GPP130 disappear.

Normally, foreign materials entering a cell get tasted by an internal compartment called an endosome. Endosomes then shunt undesirable substances to another compartment, a lysosome, where they will be broken down and their raw materials discarded or recycled.

That should spell the end of Shiga toxin — except it never reaches the lysosomes. Somewhere along the way, the poison hijacks protein-trafficking systems and forces a detour elsewhere in the cell. There the hijacker knocks out the cell’s life-sustaining machinery.

Linstedt and Somshuvra Mukhopadhyay, also of Carnegie Mellon, now show that it’s GPP130 that Shiga toxin hijacks. And manganese can defend GPP130 from that attack, allowing cells to shuttle the toxin directly to lysosomes, where it’s broken down into harmless components. In cells grown in a test tube and in mice, manganese pretreatment prevented death from the administration of pure Shiga toxin.

How clinically helpful that might be remains unclear. The toxin destroys the body’s smallest blood vessels, notes epidemiologist Dirk Werber of the Robert Koch Institute in Berlin. Vascular injury, which is the most dramatic consequence of infection with Shiga toxin-producing E. coli, “is likely to be well under way by the time infected patients seek medical attention for diarrhea,” he says.

That’s true, Tesh acknowledges, although up to seven days can pass between the onset of bloody diarrhea and catastrophic vascular effects, as the toxin breaks out of the gut and begins circulating. So there would probably be a brief window when manganese treatment could save lives, he says.

The Carnegie Mellon researchers are now homing in on the minimum amount of manganese needed to protect animals, and hope to soon begin testing using Shiga-toxin-producing E. coli.

Seaweed study fuels bioenergy enthusiasm

Seaweed has long made biofuel prospectors drool, but they hadn’t figured out how to efficiently chew through the stuff — until now. Researchers have engineered a bacterium that can break down and digest seaweed’s gummy cell walls to yield ethanol and other useful compounds. If scientists can make the process work at larger scales, seaweed could soon be a serious contender as a source of renewable fuel.

The new research “makes a pretty large leap forward,” says metabolic engineer Hal Alper of the University of Texas at Austin. Unlike corn and many other biofuel feedstocks, seaweed doesn’t need arable land, fertilizer or freshwater. If seaweed can be efficiently munched into ethanol, it broadens the biofuel horizon, says Alper, who was not involved in the research. Seaweed, he says, may be “that new source for unconventional carbon that everyone’s been looking for.”

Scientists from Bio Architecture Lab, a biofuel and renewable chemicals company headquartered in Berkeley, Calif., were interested in creating a biofuel bacterium that is a one-stop shop: They wanted a microbe that could efficiently digest the seaweed cellular building block alginate without pretreatment with chemicals or heat. Alginate is commonly used in ice creams and some textiles, but has proved difficult to break down and metabolize into fuel.

So, led by synthetic biologist Yasuo Yoshikuni, the team took the workhorse bacterium E. coli and within it, patched together the genes and other parts needed for superior seaweed-to-fuel conversion. From the marine bacterium Pseudoalteromonas, the scientists used genes for an enzyme that cuts alginate into smaller molecular bits. The researchers rigged these genes to a cellular transport system already found in E. coli, so the bacterium would secrete the alginate-slicing enzyme into its environment.

Then the team scoured scientific literature and databases for a microbe with serious alginate-digesting machinery. They hit upon the marine microbe Vibrio splendidus, and took a hefty chunk of theVibrio DNA for use in the E. coli. When the team fed alginate to their engineered E. coli, the microbes pumped out ethanol, the researchers report in the Jan. 20 Science. The system yields 80 percent of the theoretical maximum amount of ethanol for a given amount of biomass, the scientists noted, and with further tweaking will probably be even more efficient.

Part of the beauty of the system is its flexibility, says Yoshikuni. Because the alginate-degrading enzyme is released into the environment, initial breakdown products can easily be harvested for creating useful compounds such as precursors to nylon or plastics. And when E. coli consume the broken-down alginate the bacteria generate a lot of pyruvate, a chemical intermediate useful for making fuels such as butanol or biodiesel. 

Seaweed is already harvested at commercial scale in several countries for other uses, and Bio Architecture Lab is working on a pilot plant in Chile to convert seaweed into fuel, says company CEO Daniel Trunfio. Also, any seaweed will do, he notes. “We like to say we’re seaweed agnostic — we can process any brown algae.”

OFFSHORE ENERGY

Scientists have engineered a bacterium that breaks down seaweed, such as this Macrocystis species, to yield fuels such as ethanol.