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Study: Pterosaurs used 4 legs to lift off

BALTIMORE, Jan. 7 (UPI) -- Dinosaur-era pterosaurs, often referred to as pterodactyls, used their "arms" as well as their legs to leap into flight, a computerized model suggests.

In fact, pterosaurs -- believed to have died off 65 million years ago in the same cataclysm that killed off the dinosaurs on land and plesiosaurs at sea -- had much stronger "arms" than legs, which is the opposite of the way birds are built, Michael Habib, a researcher at the Johns Hopkins University medical school's Center for Functional Anatomy and Evolution, wrote in a study published in the German journal Zitteliana.

"The difference between pterosaurs and birds with regard to critical mechanical properties is very, very large, especially when you're talking about the big pterosaurs," Habib said in a statement.

"As the size gets bigger, the difference gets bigger too," he said.

His model indicated that Quetzalcoatlus pterosaurs, for instance -- one of the largest known flying animals of all time, with a 35-foot wingspan -- couldn't possibly launch themselves using their hind legs alone.

But by folding their wings and balancing on their "knuckles," they could push themselves off, almost like a leap-frogging long-jump, he said.

"Then, with wings snapping out, off they'd fly," he said.

"Using all four legs, it takes less than a second to get off of flat ground, no wind, no cliffs," Habib said.

"This was a good thing to be able to do if you lived in the late Cretaceous period and there were hungry tyrannosaurs wandering around," he said.

Habib's research was funded by the Jurassic Foundation, a non-profit organization providing funding for research on dinosaur paleobiology.

'Red tide' linked to nutrient pollution

CAMBRIDGE, Md., Jan. 7 (UPI) -- U.S. and other scientists have linked nutrient pollution to an increase in the number of harmful algal blooms, sometimes called "red tide," in coastal seas.

When harmful algal blooms occur, they taint seafood with toxins, cause human respiratory and skin irritations and cause fish or mammal kills in coastal waters.

The link to nutrient pollution, presented in 21 articles in the journal Harmful Algae, could elevate harmful algal blooms "to the forefront of coastal management issues needing immediate attention," said journal editor and University of Maryland Center for Environmental Science researcher Patricia Glibert.

The articles suggest degraded water quality from increased nutrient pollution promotes the development and persistence of many harmful algal blooms, which are a dense aggregation of phytoplankton, algae or cyanobacteria.

Understanding the complex relationships between nutrients and the outbreak of harmful algae is key to reducing future blooms, the researchers say.

They also say new tools for monitoring and predicting these events can help scientists better understand harmful algal blooms.

An international symposium on algal blooms and nutrient pollution will be held in Beijing in October.

'Scrawny' gene keeps stem cells healthy

BALTIMORE, Jan. 7 (UPI) -- The discovery of a "scrawny" gene in fruit flies may improve researchers' ability to direct stem cell differentiation in desired ways, U.S. researchers say.

The gene -- called scrawny because of the appearance of mutant adult flies -- appears to be a key factor in keeping a variety of stem cells in their undifferentiated state, the researchers at the Carnegie Institution's Department of Embryology say in an article to be published Friday in the journal Science.

"Understanding how stem cells maintain their potency has implications both for our knowledge of basic biology and also for medical applications," the researchers say in a statement.

"Our tissues, and indeed our very lives, depend on the continuous functioning of stem cells," embryology director Allan Spradling says.

"Yet we know little about the genes and molecular pathways that keep stem cells from turning into regular tissue cells -- a process known as differentiation," he says.

The study found that by controlling the proteins that wrap the genes, scrawny genes can silence other genes that would otherwise cause a generalized cell to differentiate into a specific type of cell, such as a skin or intestinal cell.

While the scrawny gene has so far only been identified in fruit flies, very similar genes that may carry out the same function are known to be present in all multicellular organisms, including humans, the researchers say.

"This new understanding of the role played by scrawny may make it easier to expand stem cell populations in culture, and to direct stem cell differentiation in desired directions," Spradling says.

How Reblochon gets its distinctive flavor

NEWCASTLE UPON TYNE, England, Jan. 7 (UPI) -- The French cheese Reblochon gets its distinctive flavor from a previously unknown group of bacteria, British university researchers report.

Using genetic fingerprinting, the researchers identified eight previously undiscovered microbes in the soft, creamy, brie-like cheese made in France's Savoy mountain region, a study published in the International Journal of Systematic and Evolutionary Microbiology said.

"It has always been thought the bacteria cheese makers were putting in at the start of the process gave Reblochon its distinctive flavor," biology professor and project lead Michael Goodfellow of Newcastle University said.

But what the research showed was that different bacteria contained in a salt solution in which the Reblochon is washed, or "smear-ripened," were more responsible for the taste, texture and smell of the cheese, he said.

The researchers named the bacteria Mycetocola reblochoni, after the cheese in which they were found.

The smear-ripening process helps to spread the bacteria across the surface of the cheese, ripening it from the outside in.

The newfound bacterial strains out-compete Brevibacterium, previously thought to provide the flavor, the researchers said.

Brevibacterium, used to ferment Limburger and Port-du-Salut cheeses, is also ubiquitously present on the human skin, where it causes foot odor.

"The next stage is to see how these new microbes might be (beneficially) used," Goodfellow said.

"Bacteria get a bad name because they are associated with causing disease, but many are extremely beneficial and our reblochoni group may well prove to have important uses," he said.