September 26, 2007, 7:53 PM CT

Working to save microscopic threatened species

The Smithsonians National Zoo recently acquired 12,000 new animalsmicroscopic Elkhorn coral larvae harvested by National Zoo researchers in Puerto Ricoas part of an international collaborative program to raise the threatened species. National Zoo researchers hope to one day return the animals, once they are grown, to their wild ocean habitat.

In August, Zoo Reproductive Scientist Dr. Mary Hagedorn and Invertebrates Keeper Mike Henley traveled to Puerto Rico with marine researchers involved with SECORE (SExual COral REproduction) to collect and artificially inseminate coral. Hagedorn is pioneering the cyropreservation (freezing, storing and thawing) of coral sperm and eggs. Working in collaboration with SECORE, she is trying to create a genome resource bank, which will help preserve the genetic diversity of coral.

Hagedorn, Henley and the team captured spawning coral gametes in nets during night dives and transferred them back to their laboratory on the beach for research and artificial inseminationoften working until 3 a.m. Using 75 feet of specially designed flexible PVC piping that could be bent around the coral so as not to harm it, the team created a water-flow system that allowed water from the ocean to continuously flow in and out of the coral larvae enclosure located in the beachfront laboratory. Keeping the water fresh and at a constant temperature is essential for corals that flourish in stable environments......... Posted by: Kelly      Read more         Source

September 25, 2007, 10:00 PM CT

How The Zebrafish Gets His Stripe

Researchers have discovered how the zebrafish (Danio rerio) develops one of its four stripes of pigment cells.

Their findings add to the growing list of tasks carried out by an important molecule that is involved in the arrangement of everything from nerve cells to reproductive cells in the developing embryo.

The research focused on a particular zebrafish mutant known as choker, which is distinctive because one of the four stripes running down its side is missing, and it has a dark collar around its neck instead.

Dark spots and stripes in fish, amphibians and reptiles are commonly caused by a type of cell, known as a melanophore, which contains high quantities of the pigment melanin.

Using time-lapse photography, the team put together movies showing how the melanophores migrate in developing embryos of both the wild-type (naturally occurring) zebrafish and the choker mutant.

At first, cells migrate through the neck region in both wild-type and choker mutant fish to generate two stripes. Then, whilst cell migration ceases in the neck region of the wild-type embryo, melanophores in the choker mutant exit from the two stripes and busily cluster around the collar region of the developing fish.

"It is as though someone has put up 'keep off the grass' signs in the wild-type zebrafish to keep the melanophores in separate paths (stripes)," said Dr Robert Kelsh from the University of Bath who led the study which was reported in the journal Development......... Posted by: Kelly      Read more         Source

September 25, 2007, 9:12 PM CT

City birds better than rural species in coping

Birds that hang out in large urban areas seem to have a marked advantage over their rural cousins they are adaptable enough to survive in a much larger range of conditions.

In fact, new research from the University of Washington suggests that the adaptability of a number of urban bird species means they don't just survive but actually thrive in what might be considered to be a very challenging environment.

"The urban habitat is commonly more severe than the habitats these birds historically occupied. Urban habitats aren't easy, so the birds have to have developed coping mechanisms," said John Wingfield, a UW biology professor involved in the research.

The study was led by Frances Bonier, a postdoctoral researcher in biology at Virginia Polytechnic Institute, who did the work as a UW doctoral student before moving to Virginia Tech. Co-author Paul Martin, now an assistant professor of biology at Queens University in Kingston, Ontario, also took part in the research as a UW doctoral student.

Ornithologists, biologists and birdwatchers around the world were sent questionnaires that asked them to list 10 common native breeding birds found in their cities. The responses produced data on 217 urban bird species from 73 of the world's largest cities and 247 rural species. To be considered "rural," a species could not be described as breeding in human-disturbed habitats such as towns and cities, and its natural breeding distribution must overlap at least one of the large cities, implying that at one time the species occupied the area where the city is now......... Posted by: Kelly      Read more         Source

September 24, 2007, 10:06 PM CT

Dams and California salmon

Spring-run Chinook salmon and other fish in the rivers of Californias Central Valley could be harmed by more water-storage dams, as per scientists at Duke University and the National Oceanic and Atmospheric Administration.

The findings of a recent paper may serve as a cautionary tale to policymakers, researchers and resource managers currently embroiled in a debate about the construction of new dams in the region.

The paper, Directed Connectivity Among Fish Populations in a Riverine Network, was reported in the September 3 online issue of Journal of Applied Ecology.

Robert S. Schick, of the University Program in Ecology at Duke's Nicholas School of the Environment and Earth Sciences, used analytical techniques from network science to study the relative importance of individual populations of salmon within the valley and examined how the addition of large water-storage dams blocked access to habitat and fragmented these populations over time.

"We observed that fragmented populations became increasingly vulnerable to disturbance and extinction," said Schick, who co-wrote the paper with Steven T. Lindley of NOAAs Southwest Fisheries Science Center in Santa Cruz, Calif.

The paper has become topical thanks to a recent $9 billion bond proposal by California Gov. Arnold Schwarzenegger to construct two new dams and expand a third in the environmentally fragile Sacramento-San Joaquin River Delta......... Posted by: Kelly      Read more         Source

September 24, 2007, 9:56 PM CT

Sunburn for us protecton for crayfish

The production of melanin gives us sunburns, but it also helps invertebrate animals to encapsulate attacking fungi and parasites. Uppsala University researchers, in collaboration with Korean and Thai colleagues, can now show that melanin also protects against bacterial infections, at least in crayfish. The study is reported in the latest Net edition of Journal of Biological Chemistry.

The production of melanin is an important protective reaction that gives us a sunburn, for instance. In invertebrate animals it has long been found that parasites, fungi, and other invaders become encapsulated in melanin. In a number of animals this can be seen as black-brown spots on the shell that show that the animal has had an infection.

"In mosquitoes that can harbor the malaria parasite it has also been found that the mosquitos ability to form such melanin capsules often determines whether it will be able to spread the disease to humans," says Haipeng Liu.

Conversely, the possible effect of melanin production on bacterial infections has been intensively debated. In the current study the researchers show, by manipulating the genetic expression of the melanin-producing enzyme, that effective melanin production is crucial to the ability of freshwater crayfish to survive an infection of an extremely dangerous bacteria for them, Aeromonas hydrophila......... Posted by: Kelly      Read more         Source

September 24, 2007, 9:46 PM CT

Rare albino ratfish has eerie, silvery sheen

A ghostly, mutant ratfish caught off Whidbey Island in Washington state is the only completely albino fish ever seen by both the curator of the University of Washington's 7.2 million-specimen fish collection and a fish and wildlife biologist with more than 20 years of sampling fish in Puget Sound.

"Ratfish commonly hang out in places with soft, muddy bottoms," says Jon Reum, the aquatic and fishery sciences doctoral student who found the albino ratfish during a UW research project. "The typical ratfish in Puget Sound is brown or black with a smattering of white spots so it blends in with the sediments".

This fish was almost pure white with a crystalline layer near the surface of its skin that gave it a silvery sheen.

"It must have been like a beacon," says Ted Pietsch, UW professor of fisheries and aquatic sciences and curator of the UW fish collection. "Why didn't it get eaten, long before this, by some predator, for example, by a spiny dogfish so common in Puget Sound and that love to devour ratfish"".

The foot-long female may have been 2 or 3 years old, Reum and Pietsch estimate, making her a teenager in the ratfish world.

She was caught this summer in about 200 feet of water during a UW research project examining the food web in Hood Canal and Puget Sound. Puget Sound is the nation's second-largest estuary in the Lower 48 after Chesapeake Bay. The city of Seattle, home to about 4 million people, is built on its shores. Puget Sound connects to the Pacific Ocean via the Strait of Juan de Fuca to the north......... Posted by: Kelly      Read more         Source

September 21, 2007, 6:39 AM CT

New Strategy To Create Genetically Modified Animals

Scientists at the University of Pennsylvania School of Veterinary Medicine have demonstrated the potential of a new strategy for genetic modification of large animals. The method employs a harmless gene treatment virus that transfers a genetic modification to male reproductive cells, which is then passed naturally on to offspring.

Ina Dobrinski, associate professor and director of the Center for Animal Transgenesis and Germ Cell Research at Penn Vet, and her colleagues introduced adeno-associated virus, AAV, to male germline stem cells in both goats and mice. The study showed that AAV stably transduced male germ line stem cells and led to transgene transmission through the male germ line.

The findings, available online in The FASEB Journal and in the February 2008 print edition, are the first report of transgenesis via germ cell transplantation in a non-rodent species, a promising approach to germ line genetic modification. It also demonstrates that germline transduction and germ cell transplantation in large animals provides an approach that is potentially less costly than microinjection and cloning, the traditional methods used to generate transgenic large animal models for biomedical research.

Scientists used mouse germ cells harvested from experimentally induced cryptorchid donor testes that were then exposed in vitro to AAV vectors carrying a green fluorescent protein transgene and transplanted to germ cell-depleted recipient testes, resulting in colonization of the recipient testes by transgenic donor cells......... Posted by: Kelly      Read more         Source

September 21, 2007, 5:30 AM CT

Key to longer life (in flies) lies in just 14 brain cells

Two years ago, Brown University scientists discovered something startling: Decrease the activity of the cancer-suppressing protein p53 and you can make fruit flies live significantly longer.

Now the same team reports an intriguing follow-up finding. The p53 protein, they found, may work its lifespan-extending magic in only 14 insulin-producing cells in the fly brain.

Its quite surprising, said Johannes Bauer, a postdoctoral research fellow at Brown. In the fruit fly brain, there are tens of thousands of cells. But we observed that it takes a reduction of p53 activity in only 14 of those brain cells to extend lifespan. It was like finding a needle in the haystack a very small needle at that.

Bauer is the lead author of the research report, reported in the Proceedings of the National Academy of Sciences. Brown biology professor Stephen Helfand, senior scientist on the project, will discuss the findings in his keynote address at the Gordon Research Conferences on the Biology of Aging, to be held Sept. 23-28, 2007, in Les Diablerets, Switzerland.

P53 is sometimes called guardian of the genome for defending cells against DNA damage. Not enough of the protein can cause cancer; too much, however, can shorten lifespan. But in 2005, Helfand and his lab showed that a targeted decrease of p53 in fruit flies a decrease specifically in their brain cells allowed flies to live healthy lives that were as much as 58 percent longer......... Posted by: Kelly      Read more         Source

September 18, 2007, 10:09 PM CT

Bats add their voice to the FOXP2 story

When it comes to the FOXP2 gene, humans have had most to shout about. Discoveries that mutations in this gene lead to speech defects and that the gene underwent changes around the time language evolved both implicate FOXP2 in the evolution of human language. More recently, patterns of gene expression in birds, humans and rodents have suggested a wider role in the production of vocalisations. Yet numerous reports have established that FOXP2 shows very little genetic variation across even distantly related vertebrates - from reptiles to mammals providing few extra clues as to the genes role.

A new study, undertaken by a joint of team of British and Chinese scientists, has observed that this gene shows unparalleled variation in echolocating bats. The results, appearing as per a research findings reported in the online, open-access journal PLoS ONE on September 19, report that FOXP2 sequence differences among bat lineages correspond well to contrasting forms of echolocation.

Like speech, bat echolocation involves producing complex vocal signals via sophisticated coordination of the mouth and face. The involvement of FOXP2 in the evolution of echolocation adds weighty support to the theory that FOXP2 functions in the sensory-motor coordination of vocalisations......... Posted by: Kelly      Read more         Source

September 18, 2007, 10:08 PM CT

More Viable Offspring If They Can Choose Their Best Mate

When it comes to picking a mate, Crosby, Stills, Nash and Young had an answer: If you cant be with the one you love, love the one youre with. As it turns out, that may be a cardinal rule in the animal kingdom, too.

New research that crosses several species boundaries shows that when animals must choose less-than-preferred (to them) mates, females and males apparently have ways to compensate that increase the chance their offspring will survive. The study, just reported in the Proceedings of the National Academy of Sciences, adds weight to the Compensation Hypothesis, a proposal that has given insight into how individuals can pass on their genes even under less than ideal circumstances.

Its always better for offspring if parents can mate with preferred partners, but its becoming clear that when parents cant have that preferred partner, they have ways of making up for it, said Patricia Adair Gowaty, a Distinguished Research Professor of Ecology and Genetics at the University of Georgia and lead author of the study. When female choosers were in enforced pairs with males they did not prefer, they laid more eggs. Similarly, when males are paired with females they do not prefer, they ejaculate more sperm. This compensation seems to be a way of making the best of a bad job......... Posted by: Kelly      Read more         Source