November 7, 2007, 8:07 PM CT

Helping to fight widespread potato disease

Researchers have made a key discovery into the genetics of the bacteria that causes blackleg, an economically damaging disease of potatoes, that could lead to new ways to fight the disease. The scientists at the University of Cambridge, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), observed that if a particular gene is inactivated in the bacterium Erwinia carotovora, its ability to damage the plant and cause disease is severely impeded. The research was recently reported in the Journal of Bacteriology.

Erwinia carotovora can cause disease in a wide range of plants, including carrots, tomatoes and onions, but is best known in temperate regions for causing blackleg and soft rot in potatoes. Its success partly lies in its ability to produce enzymes which break down its hosts cell walls. The degraded cell walls provide nutrients to the bacterium, and so aid its survival and growth.

The Cambridge scientists discovered that if they inactivated a gene called relA, which helps the bacteria recognise when nutrients are running low, then the bacterias ability to export enzymes to break down the plants cell walls is also abolished.

Research leader Dr Martin Welch explains: Blackleg is a significant economic problem, substantially reducing crop yields......... Posted by: Erica      Read more         Source

November 7, 2007, 8:01 PM CT

Prairie verbena: conserves water, drought-tolerant

Prairie verbena, a common wildflower, grows from the Mississippi River to Arizona and from Southern Mexico to South Dakota. This beautiful native plant can be seen covering large areas of plains, prairies, pastures, and roadsides, often from March through October.

Working to create a new drought-resistant and water-saving wildflower, researchers at Texas Tech University's Department of Plant and Soil Science have introduced 'Raider Amethyst', a new cultivar of common prairie verbena. Cynthia McKenney, Associate Professor of Horticulture at Texas Tech, says that Raider Amethyst was bred for homeowners and landscape architects who are interested in using more environmentally adapted materials in home gardens and public use areas. McKenney noted, "This project was to develop an improved wildflower release that would provide more compact, dependable color in a water-conserving landscape".

Raider Amethyst, or Glandularia bipinnatifida, is the second addition to the Raider Wildflower collection, following Melampodium leucanthum 'Raider White', usually known as blackfoot daisy. It is recommended for use in low-maintenance plantings and water-conserving landscapes. It grows throughout the season with minimal care. Raider Amethyst is now available as commercial and experimental seed......... Posted by: Erica      Read more         Source

November 7, 2007, 7:14 PM CT

Tropical importance in biodiversity

Even a group of shellfish that appear to violate the overarching pattern of global biodiversity actually follows the same biological rules as other marine organisms, confirming a general theory for the spread of life on Earth. The University of Chicago's David Jablonski and colleagues present this finding this week in the advanced online edition of the Proceedings of the National Academy of Sciences.

"There's more of everything in the tropics. More genetic diversity, more diversity in form, more diversity of species," said David Jablonski, the William R. Kenan Jr. Professor in Geophysical Sciences at Chicago. Biologists call this the "latitudinal diversity gradient." They have known about this phenomenon for more than a century, "but there's remarkably little agreement on how it's formed," Jablonski said.

Researchers have offered dozens of different theories to explain the evolutionary underpinnings of the tropics' rich biodiversity. In their Proceedings article, Jablonski, the University of Chicago's Andrew Krug and the University of California, Berkeley's James Valentine present findings that highlight the importance of the tropics in maintaining the entire planet's biodiversity.

Researchers had debated for three decades whether the tropics were a cradle of diversity, where new species originate, or a museum of diversity, where old species persist. Last year Jablonski, Valentine and Kaustuv Roy of the University of California, San Diego, potentially resolved the debate by showing that the tropics is both a cradle and a museum of biodiversity......... Posted by: Kelly      Read more         Source

November 5, 2007, 9:06 PM CT

Worms take the sniff test

Buttery popcorn or fresh green vegetables? Your answer tells a lot about you.

Now, researchers say that the way that thousands of tiny worms have answered that question likely reveals a lot about you and your brain, too.

In the experiment at the University of Rochester Medical Center, worms that are hermaphrodites (with characteristics of both females and males) went for the buttery smell, while the males the other of the two sexes in these worms opted for the scent of fresh vegetables. But when scientists tricked a few nerve cells in hermaphrodites into sensing that they were in a male worm, suddenly they too preferred the smell of fresh vegetables.

While the olfactory likes and dislikes of the tiny roundworm known as C. elegans is the stuff of distinctive cocktail conversation, trivia is the furthest thing on the minds of Rochester researchers who did the study, which is being reported in the Nov. 6 issue of Current Biology.

Geneticist Douglas Portman, Ph.D., and graduate student KyungHwa Lee ultimately hope to understand gender differences in diseases like autism, depression, and attention-deficit disorder. A number of more boys than girls are diagnosed with ADD and autism, and a number of more girls than boys are diagnosed with depression. While proposed explanations abound, few researchers debate the notion that the brains of the sexes are in some ways fundamentally different......... Posted by: Kelly      Read more         Source

November 5, 2007, 8:21 PM CT

Potential to double tiger numbers in South Asia

Scientists at the Wildlife Conservation Society and other institutions declare that improvements in management of existing protected areas in South Asia could double the number of tigers currently existing in the region.

The study appears in the most recent edition of the journal Biological Conservation.

Specifically, the study examined 157 reserves throughout the Indian subcontinentcomprising India, Bangladesh, Bhutan, and Nepal. It observed that 21 of the protected areas meet the criteria needed for large healthy tiger populations. Further, the study noted that these protected areas have the potential to support between 58 percent and 95 percent of the subcontinents potential tiger capacity, estimated to be between 3,500 to 6,500 tigers. In the absence of reliable data to produce a reliable estimate, tiger conservationists say that the big cats may currently number between 1,500 to 4,000 animals in the four countries combined.

The small improvements to increase tiger populations cited in the study include better funding, increasing staff support, restoring tiger habitat, and stepping up enforcement activities that focus on preventing the poaching of tigers and their prey.

We were happy to find that the most important reserves identified in the study already have made tiger conservation a priority, said the lead author Dr. Jai Ranganathan of the National Center for Ecological Analysis and Synthesis......... Posted by: Kelly      Read more         Source

November 5, 2007, 8:14 PM CT

Kids have a compass, but adults have the map

Even bird brains can get to know an entire continent -- but it takes them a year of migration to do so, suggests a Princeton research team.

The researchers have shown that migrating adult sparrows can find their way to their winter nesting grounds even after being thrown off course by thousands of miles, adjusting their flight plan to compensate for the displacement. However, similarly displaced juvenile birds, which have still not made the complete round trip, are only able to orient themselves southward, indicating that songbirds' innate sense of direction must be augmented with experience if they are to find their way home.

"This is the first experiment to show that when it comes to songbird migration, age makes a difference," said team member Martin Wikelski, an associate professor of ecology and evolutionary biology. "The results indicate that the adult birds possess a navigational map that encompasses at least the continental U.S., and possibly the entire globe."

Two longstanding questions about migrant songbirds are how quickly they recover when thrown off course -- as they can be when they encounter powerful winds -- and just what navigational tools they use to do so. To address the two questions, the team decided to fit a group of white-crowned sparrows with tiny radio transmitters no heavier than a paper clip and track their movements from a small plane......... Posted by: Kelly      Read more         Source

November 4, 2007, 8:11 PM CT

Divers find new species in Aleutians

There are unknown creatures lurking under the windswept islands of the Aleutians, as per a team of scientific divers from the University of Alaska Fairbanks.

This summer, while completing the second phase of a two-year broad scientific survey of the waters around the Aleutian Islands, researchers have discovered what may be three new marine organisms. This year's dives surveyed the western region of the Aleutians, from Attu to Amlia Island, while last year's assessment covered the eastern region.

During the dives, two potentially new species of sea anemones have been discovered. Stephen Jewett, a professor of marine biology and the dive leader on the expedition, says that these are "walking" or "swimming" anemones because they move across the seafloor as they feed. While most sea anemones are anchored to the seabed, a "swimming" anemone can detach and drift with ocean currents. The size of these anemones ranges from the size of a softball to the size of a basketball.

Another new species is a kelp or brown algae that researchers have named the "Golden V Kelp" or Aureophycus aleuticus. As per Mandy Lindeberg, an algae expert with NOAA's National Marine Fisheries Service and a member of the expedition, the kelp may represent a new genus, or even family, of the seaweed. Up to ten feet long, the kelp was discovered near thermal vents in the region of the Islands of the Four Mountains......... Posted by: Kelly      Read more         Source

November 1, 2007, 8:12 PM CT

The Watchdogs of chromosome-segregation

There is always a cell from the outset, no matter if the cell is from worms, frogs or human beings. To begin with, a cell creates identical copies of chromosomes during the cell cycle, which are then distributed to existing daughter cells. The multiplication to a multi-cellular organism is made possible through the subsequent cell division or "cytokinesis", a marvel of nature. Through these means the daughter cells receive a complete batch of genetic information. Cancer or strong genetic illnesses arise when chromosomes are unequally divided during cell division.

A central role in the segregation process of the chromosomes plays the chromosomal passenger complex, CPC. It is a dynamic protein complex which is first binding to the centromer, a central anchor at the chromosomes at which the chromosomal spindle, a network of protein filaments, attaches. The chromosomes are drawn by the spindle to each pole of the cell before it is going to be separated into two daughter cells. CPC is guaranteeing that the chromosomes are binding properly at the spindle. Up to now it was known that the watchdogs of the cell division consist of four subunits which all have to be present for accurate chromosome segregation. For the detailed understanding of their regulation researchers at the MPI of Biochemistry in collaboration with scientists at the EMBL solved the crystal structure of the regulatory core of CPC......... Posted by: Janet      Read more         Source

Fri, 02 Nov 2007 01:42:00 GMT

Multidrug Resistance Transporters

Ever since the discovery of penicillin, we have lived our lives with far less fear of infectious disease. In the decades since then, a wide variety of drugs have been isolated from natural sources or synthesized by chemists, giving our doctors a large arsenal of antibiotics to fight infection. Bacteria, however, are dynamic evolving organisms, and they have developed many methods to fight back. In some cases, they develop ways to destroy antibiotic drugs directly, for instance, some bacteria make beta-lactamase enzymes that break down penicillin. In other cases, the bacteria change their own molecular machinery, making it invulnerable to the drugs. For instance, methicillin-resistant Staphylococcus bacteria use new, resistant enzymes to build their cell walls. If these methods don’t work, bacteria also have a more general method. They build special pumps that transport many different antibiotics out of the cell before they can do their job.

Multidrug resistance transporters find drugs that trying to gain entry through a cell membrane and they transport them back outside. The one shown here, Sav1866 from PDB entry 2onj, is found in Staphylococcus bacteria. The protein is composed of two identical subunits with a tunnel in between. Drugs enter the tunnel, and then cleavage of ATP in the large portion at the bottom causes a scissoring motion, opening the tunnel on the outer side and releasing the drug. This structure captures the protein in this final state, ready to release drugs upwards towards the outside of the cell membrane.

Read the rest from David Goodsell, here. Posted by: PhilipJ      Read more     Source

Fri, 02 Nov 2007 00:53:02 GMT

The Inner Life Of The Cell

The Inner Life of the Cell is an animation by Alain Viel and Robert Lue of Harvard University. It vividly illustrates the mechanisms that allow a white blood cell to sense its surroundings and respond to an external stimulus. This animation explores the different cellular environments in which these communications take place.



(via Dark Roasted Blend) Posted by: Gerard      Read more     Source