December 9, 2010, 7:55 AM CT

mouse from 2 fathers

Using stem cell technology, reproductive researchers in Texas, led by Dr. Richard R. Berhringer at the M.D. Anderson Cancer Center, have produced male and female mice from two fathers.

The study was posted today (Wednesday, December 8) at the online site of the journal Biology of Reproduction

The achievement of two-father offspring in a species of mammal could be a step toward preserving endangered species, improving livestock breeds, and advancing human assisted reproductive technology (ART). It also opens the provocative possibility of same-sex couples having their own genetic children, the scientists note.

In the work reported today, the Behringer team manipulated fibroblasts from a male (XY) mouse fetus to produce an induced pluripotent stem (iPS) cell line. About one percent of iPS cell colonies grown from this XY cell line spontaneously lost the Y chromosome, resulting in XO cells. The XO iPS cells were injected into blastocysts from donor female mice. The treated blastocysts were transplanted into surrogate mothers, which gave birth to female XO/XX chimeras having one X chromosome from the original male mouse fibroblast.

The female chimeras, carrying oocytes derived from the XO cells, were mated with normal male mice. Some of the offspring were male and female mice that had genetic contributions from two fathers......... Posted by: Kelly      Read more         Source

December 8, 2010, 7:19 AM CT

Bird call database nests online

A growing online library of bird sounds, photos and information offers a new resource for backyard birders and seasoned ornithologists alike.

The Avian Vocalizations Center at Michigan State University, or AVoCet,offers free downloads of bird sounds from around the world. It also features sonograms that visually chart the sounds, photos of birds recorded, Google Earth maps of recording locations and links to other online sound collections.

More than 10,200 recordings from over 3,190 species in 45 countries are now available on AVoCet, "and that's growing quickly," said Pamela Rasmussen, an assistant professor of zoology and assistant curator at the MSU Museum. "Soon recordings and their data from a number of more species and areas will be available for download from AVoCet".

There are, after all, 10,000 bird species, all of which make sounds of some type. A number of birds, such as cardinals, even sing in regional dialects. Some birds have huge vocabularies a single male Brown Thrasher is known to give 2,000 different notes.

Author of an exhaustive reference work on the birds of South Asia, Rasmussen haccording tosonally recorded on all the continents for this project. Her work in the Philippines alone netted 597 recordings of 120 species, a number of of which are threatened. Some of those sound types are not publicly available anywhere other than AVoCet......... Posted by: Kelly      Read more         Source

December 7, 2010, 7:40 AM CT

Life Histories of Dead Whales

Dead whales that sink down to the seafloor provide a feast for deep-sea animals that can last for years. Prior research suggested that such "whale falls" were homes for unique animals that lived nowhere else. However, after sinking five whale carcasses in Monterey Canyon, scientists from the Monterey Bay Aquarium Research Institute (MBARI) observed that most of the animals at these sites were not unique to whale falls, but were common in other deep-sea environments as well. Nonetheless, the whale-fall communities did include a few very abundant animals that were "bone specialists," including 15 species of bone-eating Osedax worms and several newly discovered species of bone-eating snails.

In 2004, evolutionary biologist Robert Vrijenhoek and colleagues announced the discovery of a new family of bone-eating worms, which they found two years earlier living on a dead whale in Monterey Canyon, almost 3,000 meters below the sea surface.

Following this discovery, Vrijenhoek's team set out to study how these worms survived, reproduced, and spread from one whale carcass to another. To this end, MBARI scientists and marine operations staff hauled five very smelly dead whales off the beaches of Monterey Bay, attached weights to the carcasses, and sank them at different depths in Monterey Canyon......... Posted by: Kelly      Read more         Source

November 23, 2010, 7:58 AM CT

The Puzzle of Biological Diversity

Biologists have long thought that interactions between plants and pollinating insects hasten evolutionary changes and promote biological diversity. However, new findings show that some interactions between plants and pollinators are less likely to increase diversity than previously thought, and in some instances, reduce it.

Findings, reported in the Journal of Evolutionary Biology, show that local populations of one of the most distinctive plants in the Mojave Desert, the Joshua tree, are not as biologically diverse as would be expected. Joshua trees cannot produce seeds without specialized moths pollinating the tree's flowers. Prior research has shown that biological diversity exists among species of Joshua trees and their pollinating moths: Moths with longer ovipositors, the part of the moth used to lay eggs, favor trees with large flowers, while smaller moth species favor smaller flowers. Thus, biologists would expect the moths would adapt this trait to local flower populations and vice versa in order to reproduce. Yet using a combination of mathematical modeling and field studies, scientists observed little biological diversity among populations and thus no evidence that local populations of moths adapt to local populations of Joshua trees.

"We had previously observed two species of moths and have shown that the larger moth species uses large flowers and the smaller moth species uses smaller flowers. However, once we account for this difference, there no evidence that moths have adapted to flowers," said William Godsoe, the study's main author and postdoctoral researcher at the National Institute for Mathematical and Biological Synthesis......... Posted by: Kelly      Read more         Source

November 18, 2010, 7:38 AM CT

Hearing loss study reveals role of bone hardness

Researchers are reporting the first direct evidence that a subtle change in the physical properties of a tissue can affect its function. The finding has immediate implications for understanding several rare hearing disorders, they said, and ultimately could offer insight into such conditions as osteoporosis, arthritis, cardiovascular disease and cancer.

In their study, the researchers discovered that blocking the function of a particular molecule in the ear bone of mice decreased the hardness of the bone, causing hearing loss. Reactivating the molecule restored the bone's hardness - and the animals' hearing.

The research likely explains the previously unknown cause of hearing loss in the human disease cleidocranial dysplasia, a genetic bone syndrome,said co-author Lawrence Lustig, MD, UCSF professor of otolaryngology, and may explain hearing loss linked to some other bone diseases.

More broadly, the finding reveals the molecular pathway that regulates the physical properties of extracellular matrix - the interlocking mesh of molecules between cells - in the ear's cochlear bone. The matrix is responsible for the hardness of human tissues, ranging from stiff bone and enamel to compliant brain and skin.

Perhaps most intriguing is the discovery that variations in the physical properties of extracellular matrix affect tissue function. This finding should lead to insights into abnormal matrix properties in the tissues of diseases throughout the body, the scientists said, including osteoporosis and arthritis......... Posted by: Kelly      Read more         Source

November 18, 2010, 7:35 AM CT

Breeding Critically Endangered Tree Frog

As frogs around the world continue to disappear-a number of killed by a rapidly spreading disease called chytridiomycosis, which attacks the skin cells of amphibians-one critically endangered species has received an encouraging boost. Eventhough the La Loma tree frog, Hyloscirtus colymba, is notoriously difficult to care for in captivity, the Panama Amphibian Rescue and Conservation Project is the first to successfully breed this species.

"We are some of the first scientists to attempt to breed these animals into captivity and we have very little information about how to care for them," said Brian Gratwicke, international coordinator for the project and a research biologist at the Smithsonian's National Zoo, one of nine project partners. "We were warned that we might not be able to keep these frogs alive, but through a little bit of guesswork, attention to detail and collaboration with other husbandry experts-we've managed to breed them. The lessons we're learning have put us on target to save this incredible species and our other priority species in Panama".

The rescue project currently has 28 adult La Loma tree frogs and four tadpoles at the Summit Municipal Park outside of Panama City, Panama. In addition to the La Loma tree frog, the project also has successfully bred the endangered Limosa harlequin frog, Atelopus limosus. Keepers will continue to carefully monitor the tadpoles of both species......... Posted by: Kelly      Read more         Source

November 18, 2010, 7:28 AM CT

Indicator of fisheries health questioned

The most widely adopted measure for assessing the state of the world's oceans and fisheries led to inaccurate conclusions in nearly half the ecosystems where it was applied.

The new analysis waccording toformed by an international team of fisheries scientists, and is reported in this week's issue of the journal Nature

"Applied to individual ecosystems it's like flipping a coin; half the time you get the right answer and half the time you get the wrong answer," said Trevor Branch, a University of Washington (UW) aquatic and fisheries scientist.

"Monitoring all the fish in the sea would be an enormous, and impossible, task," said Henry Gholz, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which co-funded the research with NSF's Division of Ocean Sciences.

"This study makes clear that the most common indicator, average catch trophic level, is a woefully inadequate measure of the status of marine fisheries".

In 1998, the journal Science published a groundbreaking paper that was the first to use trends in the trophic levels of fish that were caught to measure the health of world fisheries.

The trophic level of an organism shows where it fits in food webs, with microscopic algae at a trophic level of one and large predators such as sharks, halibut and tuna at a trophic level around four......... Posted by: Kelly      Read more         Source

November 11, 2010, 8:04 AM CT

Sharks and wolves: predator, prey interactions

There appears to be a number of similarities between the importance of large predators in marine and terrestrial environments, scientists concluded in a recent study, which examined the interactions between wolves and elk in the United States, as well as sharks and dugongs in Australia.

In each case, the major predators help control the populations of their prey, researchers said. But through what's been called the "ecology of fear" they also affect the behavior of the prey, with ripple impacts on other aspects of the ecosystem and an ecological significance that goes far beyond these species.

The study was done by researchers from Oregon State University and the University of Washington, and was published in Frontiers in Ecology and the Environment, a professional journal.

"For too long we've looked at ecosystem functions on land and in the oceans as if they were completely separate," said William Ripple, a professor in the Department of Forest Ecosystems at Society at OSU, and an international expert in the study of large predators such as wolves and cougars.

"We're now finding that there are a number of more similarities between marine and terrestrial ecosystems than we've realized," Ripple said. "We need to better understand these commonalities, and from them learn how interactions on land appears to be a predictor of what we will see in the oceans, and vice versa"......... Posted by: Kelly      Read more         Source

November 8, 2010, 7:41 AM CT

New insect birth control strategy

Using pests as part of an insect birth control program helps to get rid of them, UA scientists find. A new approach that combines the planting of pest-resistant cotton and releasing large numbers of sterile moths has virtually eliminated of the world's most destructive cotton pests from Arizona.

The novel control strategy, reported in the Nov. 7 advance online publication of the journal Nature Biotechnology, has allowed growers to maintain high cotton yields without spraying insecticides to control pink bollworm.

"We are running the pesticide treadmill in reverse," said Bruce Tabashnik, department head of entomology in the UA's College of Agriculture and Life Sciences. "Our new approach has resulted in huge environmental gains. We are using cutting-edge technology to create sustainable cotton farming practices".

The new approach is part of a multi-pronged team effort to eradicate pink bollworm from the southwestern US and Mexico, in which Tabashnik and his coauthors play a leading role.

Caterpillars of the pink bollworm (Pectinophora gossypiella) are one of the most detrimental pests to cotton production worldwide. First detected in the US in 1917, this invasive insect species wreaked havoc on Arizona's cotton growing industry, with larvae infesting as a number of as every other cotton boll (the fruit capsule containing the precious threads)......... Posted by: Kelly      Read more         Source

November 5, 2010, 7:55 AM CT

Polar bears can't eat geese into extinction

As the Arctic warms, a new cache of resourcessnow goose eggsmay help sustain the polar bear population for the foreseeable future. In a newly released study published in an early online edition of Oikos, scientists affiliated with the Museum show that even large numbers of hungry bears repeatedly raiding nests over a number of years would have a difficult time eliminating all of the geese because of a mismatch in the timing of bear arrival on shore and goose egg incubation.

"There have been statements in popular literature indicating that polar bears can extirpate snow geese quickly once they start to eat eggs," says Robert Rockwell, a research associate in the Division of Vertebrate Zoology at the Museum and a professor at the City University of New York. "However, there will always be the occasional mismatch in the overlap between the onshore arrival of bears and the incubation period of the geese. Even if the bears eat every egg during each year of complete 'match,' our model shows that periodic years of mismatch will provide windows of successful goose reproduction that will partially offset predation effects."

In the last few years, work along the Cape Churchill Peninsula of western Hudson Bay by Rockwell and his colleagues has suggested that polar bears are not as hamstrung by their environment as a number of biologists believe. One new nutritional option for polar bears is the bounty of goose eggs which had previously hatched into goslings that were gone by the time bears came ashore. In recent years, 'early' bears have left breaking sea ice to come ashore and consume eggs. In fact, the earlier the bears come ashore, the better: eggs are higher in nutrients when the embryo is younger......... Posted by: Kelly      Read more         Source