April 30, 2007, 6:56 PM CT

Plants with male and bisexual flowers on the same plant

What would be the opening chapter of the Kamasutra of plant sex? A good pick would be a description of the numerous ways in which plants arrange their sexual organs: from both sexes in the same flower to sexes separated in different flowers or individuals. One widespread sexual strategy that remains an evolutionary enigma is the production of both male and bisexual flowers in the same plant, which occurs in approximately 4000 species. What is the advantage of producing these redundant male flowers? Mario Vallejo-Marin and Mark Rausher, evolutionary biologists from Duke University, report that producing male flowers can make a plant a better mother, in the recent issue of the American Naturalist. The authors showed this counter-intuitive benefit of a "male" strategy through a series of field experiments with horsenettle, a common weed in North Carolina. The experimental demonstration that male flowers can sometimes increase seed number supports a new interpretation that male flowers increase not only male but also female reproductive success.

So what is the mechanism through which male flowers increase female reproductive success? Such a benefit may arise if resources saved by producing smaller male flowers are reallocated to increased seed production, if male flowers are more attractive to pollinators, or if male flowers remove less pollen from pollinators than bisexual flowers, thus increasing the amount of non-self pollen available for fruit-producing flowers. Which one of these mechanisms is responsible for the "good mothers" in Vallejo-Marin and Rausher's study? "We don't know yet," says Mario, "but these alternatives could easily be tested through more experiments." Data from an unrelated study indicate that the female advantage of producing male flowers is not unique to horsenettle. To what extent strategies traditionally interpreted as "male" also benefit female fitness in other species remains an open and interesting question......... Posted by: Erica      Read more         Source

April 30, 2007, 6:39 PM CT

Major Advance In Structural Biology

Researchers from Baylor College of Medicine (BCM) and Rice University have discovered a new way to analyze the moving parts of large proteins a breakthrough that will make it easier for structural biologists to classify and scrutinize the active sites of proteins implicated in cancer and other diseases.

The breakthrough research will appear online this week and in an upcoming edition of the Proceedings of the National Academy of Science (PNAS). In involves a new mathematical algorithm that narrows down all the possible ways a protein might flex and bend. The math is used in conjunction with information captured via X-ray crystallography, a technique in which protein crystals are bombarded with X-rays, producing a diffraction pattern that reveals the precise three-dimensional arrangement of every atom in the protein.

"Increasingly, our discipline is faced with deciphering the structure of large, complex proteins in which some parts are constantly moving, even when the protein is locked in a crystal form," said lead researcher Jianpeng Ma, who holds joint appointments at both BCM and Rice. "We expect our method to be especially useful in refining very large and flexible supramolecular complexes with limited diffraction data".

Nobel laureate William Lipscomb of Harvard University, one of the founding fathers of protein crystallography in the North America, said, "This recent success in X-ray crystallographic refinement is revolutionary for the field of structure biology in terms of improving large and flexible complex structures that are becoming far more abundant nowadays. It is one of the largest technical leap-forwards in X-ray refinement in the last two decades. It will fundamentally change the way people do structural refinement for large and flexible complexes"......... Posted by: Janet      Read more         Source

April 29, 2007, 7:29 PM CT

Female ticks have market on gluttony

Sex makes you fat. If you're a female tick, that is.

The "truly gluttonous" female ixodid tick increases her weight an astounding 100 times her original size after she mates, so a University of Alberta researcher investigated what it is about copulation that triggers such a massive weight gain.

In a new research paper reported in the Journal of Insect Physiology, Dr. Reuben Kaufman, from the Department of Biological Sciences, suggests several differences between the ixodid tick and her blood-sucking counterparts that help explain the weight gain. Using mosquitoes, tsetse flies, bed bugs and kissing bugs as comparison, Kaufman observed that no one in comparison to this female African tick when it came to weight gain following mating.

Kaufman suggests that the ixodid tick displays a significant difference in lifestyle from the other insects and that it is adaptive for the virgin to remain small before mating.

First, this species of tick remain on the host for many days, rather than minutes. "In this family of ticks, mating takes place on the host," says Kaufman. "Most other insects mate before or after their brief blood meal -the two acts are totally separate, but not with these ticks."

Female ticks require six to 10 days to engorge fully. First, she attaches herself to the skin. Then she feeds to 10 times her unfed weight and finally, after copulation she increases her weight a further tenfold......... Posted by: Kelly      Read more         Source

April 29, 2007, 7:25 PM CT

The Chimpanzee Stone Age

Before this study, chimpanzees were first observed using stone tools in the 19th century. Now, thanks to this new archaeological find, tool use by chimpanzees has been pushed back thousands of years. The authors suggest this type of tool use could have originated with our common ancestor, instead of arising independently among hominins and chimpanzees or through imitation of humans by chimpanzees.

This study confirmed that chimpanzees and human ancestors share for thousands of years several cultural attributes once thought exclusive of humanity, including transport of raw materials across the landscape; selection and curation of raw materials for a specific type of work and projected usage; habitual reoccupation of sites where garbage and debris accumulate; and the use of locally available resources. Nut cracking behaviour in chimpanzees is transmitted socially, and the new discoveries presented in this study shows that such behaviour has been transmitted over the course of many chimpanzee generations. Chimpanzee prehistory has deep roots!

The study of our living closest relative, the chimpanzee, constantly highlights new aspects of human evolution, and a better protection of this endangered species will guarantee that we can continue uncovering new facets of our past. Relevant finds come from all parts of the African continent, including the rainforest, and not just the classical east African homeland......... Posted by: Kelly      Read more         Source

April 29, 2007, 4:00 PM CT

Bill To Protect Bristol Bay

Representatives Jay Inslee (D-WA), Wayne Gilchrest (R-MD), and Maurice Hinchey (D-NY) has recently introduced legislation in the U.S. House of Representatives that would permanently prohibit oil and gas leasing in Bristol Bay, Alaska and the surrounding waters in the Bering Sea.

On January 9, 2007, President Bush rescinded a long-standing presidential moratorium that prohibited drilling in Bristol Bay. In July, the Minerals Management Service will release a 5-year plan that is expected to recommend oil and gas development in Bristol Bay and other areas along our nation's fragile coastlines.

"Congressmen Inslee, Gilchrest and Hinchey are coming to the rescue of Bristol Bay, and all the people who depend on it, at its time of greatest need," said Carter Roberts, president and CEO of World Wildlife Fund. "Oil and gas drilling in Bristol Bay is a risk we can't afford to take. It would jeopardize the nation's most important fishery, hundreds of communities reliant on fishing and a treasure trove of wildlife".

Bristol Bay is the epicenter of the Bering Sea fishery whose commercial salmon, halibut, herring and crab fisheries generate more than $2 billion annually. Sport hunters and fishermen flock to the bay each year, pumping millions more into the economy. And the region's spectacular wildlife supports scores of Alaskan natives who rely on a healthy ecosystem for food......... Posted by: Kelly      Read more         Source

April 29, 2007, 3:57 PM CT

First-Ever Camera Trap Video of Rare Borneo Rhino

WWF has captured the first-ever "camera trap" footage of a species that just a few people have ever seen. WWF and Malaysia's Sabah Wildlife Department released footage of a Borneo Rhino which shows it eating, walking to the camera and sniffing the equipment. The first still photo of a Borneo rhino was captured only last year.

Researchers estimate there are between 25 and 50 rhinos left on the island of Borneo, the last survivors of the Bornean subspecies of Sumatran rhinos. The rhinos live only in the interior forests of Sabah, Malaysia, an area known as the "Heart of Borneo."

"These are very shy animals that are almost never seen by people," said Mahedi Andau, director of the Sabah Wildlife Department. "This video gives us an amazing opportunity to spy on the rhino's behavior."

There have been no confirmed reports of rhinos on Borneo apart from those in Sabah for almost 20 years, leading experts to fear that the species may now be extinct on the rest of the island. The rhino's threats include poaching, illegal encroachment into key rhino habitats, and the fact that the remaining rhinos are so isolated that they may rarely or never meet to breed.

"This astonishing footage captures of one of the world's most elusive creatures," said Carter Roberts, CEO and president of World Wildlife Fund. "Tremendous progress has been made in recent years to secure the rhino's habitat but so much more needs to be done considering this species may very well disappear in the next 10 years"......... Posted by: Kelly      Read more         Source

April 29, 2007, 12:14 AM CT

Elephants as Roadkill

What was once the remote heart of wild Africa has become an increasingly fragmented wilderness, crisscrossed with roads and swarming with human activity. The new roads that cut through the Congo Basin have spawned numerous human settlements and serve as direct conduits for loggers and poachers who come seeking the forest's bounty. For the little-known forest elephant, a native of the forests of west and central Africa, researchers are calling these roads highways of death.

A new study coordinated by the Wildlife Conservation Society (WCS) observed that as encroachment into the forest increases, elephant numbers are plummeting, especially near roadways where ivory poachers travel. A booming illegal ivory trade to China and other countries is driving poaching in central Africa. In response to the new threat, elephants are retreating to the remote depths of national parks.

The researchers walked more than 3,700 miles in five countries, covering more than 26,000 square miles. They counted elephant dung to tally individuals as well as elephant carcasses left behind by poachers. The surveys were conducted under the auspices of MIKE (Monitoring of the Illegal Killing of Elephants), a program authorized by a resolution from the Convention on International Trade in Endangered Species of Flora and Fauna (CITES) to look at poaching trends. Forest elephants have not been previously studied on this scale since 1989, when their population was estimated at 170,000 individuals......... Posted by: Kelly      Read more         Source

April 29, 2007, 12:11 AM CT

Good News for Gorillas

Mountain gorillas are still hanging tough in Uganda's Bwindi Impenetrable National Park, one of only two places in the world where these endangered great apes live. A recent census in the park observed that the population has increased by 6 percent since the last census in 2002, up from 320 to 340 individual gorillas. Staff from Uganda Wildlife Authority, Wildlife Conservation Society (WCS), Max Planck Institute of Anthropology, and other groups conducted the latest survey between April and June 2006.

"This is great news for all of the organizations that have worked to protect Bwindi and its gorillas," said WCS researcher Dr. Alastair McNeilage, who also directs the Institute of Tropical Forest Conservation in Bwindi. "There are very few cases in this world where a small population of endangered primates is actually increasing".

The scientists surveyed the distribution, size, and makeup of the Bwindi population, and gauged human impacts on the gorillas. Because the gorillas inhabit a relatively small area-Bwindi Impenetrable National Park covers only 127 square miles-the team was able to count every family group in the forest. In addition to tallying trails and nests, they used genetic samples from fecal specimens to identify and distinguish individual gorillas......... Posted by: Kelly      Read more         Source

April 24, 2007, 11:13 PM CT

Planarians Offers Insight Into Germ Cell Development

The planarian is not as well known as other, more widely used subjects of scientific study - model creatures such as the fruit fly, nematode or mouse. But University of Illinois cell and developmental biology professor Phillip Newmark thinks it should be. As it turns out, the tiny, seemingly cross-eyed flatworm is an ideal subject for the study of germ cells, precursors of eggs and sperm in all sexually reproducing species.

The planarian Newmark studies, Schmidtea mediterranea, is a tiny creature with a lot of interesting traits. Cut it in two (lengthwise or crosswise) and each piece will regenerate a new planarian, complete with brains, guts and - in most cases - gonads. Even when the planarian's brain is severed from its body, it can regenerate all that is removed, including the reproductive organs.

In a new study published this month in the Proceedings of the National Academy of Sciences, Newmark and colleagues at the U. of I. report that planarians share some important characteristics with mammals that may help researchers tease out the mechanisms by which germ cells are formed and maintained. Newmark's team made a few discoveries correlation to a gene, called nanos, which was previously known to play a critical role in germ cell development in several other model organisms......... Posted by: Janet      Read more         Source

April 24, 2007, 11:07 PM CT

Hibernating Bears Conserve More Strength

A fascinating new study from the May/June 2007 issue of Physiological and Biochemical Zoology quantifiably measures the loss of strength and endurance in black bears during long periods of hibernation. T.D. Lohuis (Alaska Department of Fish and Game) and his coauthors find that black bears in hibernation lose about one-half as much skeletal muscle strength as humans confined to bed rest for similar periods of time do.

"Fasting, unweighting, or immobility results in compromised muscle function," explain the authors. They continue, "Because bears are confined and anorexic for several months during winter but can still retain muscle protein and display sustained activity if disturbed, we measured skeletal muscle strength, fatigue resistance, and in vivo contractile properties of intact muscles in bears within their natural dens".

Adapting a system used for the evaluation of neuromuscular disease progression in humans, the scientists tested black bears from Middle Park, Colorado, both early and late in the hibernation cycle. After sampling, bears were placed back in their den, and the entrance was covered with pine boughs and snow.

The scientists observed that after 110 days of anorexia and confinement in the den, bears lost about 29% of their muscle strength. In comparison, humans on a balanced diet but confined to bed for 90 days have been reported to lose 54% of their strength. Other studies have shown that human astronauts in a weightless environment lose 9%11% of their strength during a 17-day spaceflight......... Posted by: Kelly      Read more         Source