July 6, 2010, 7:16 AM CT

Salmon in hot water

Rearing juvenile salmon at the relatively high temperature of 16C causes skeletal deformities in the fish. Scientists writing in the open access journal BMC Physiology investigated both the magnitude and mechanisms of this effect, which occurs when salmon farmers use warmed water to increase fish growth rates.

Harald Takle worked with a team of scientists from NOFIMA (the Norwegian Institute of Food, Fisheries and Aquaculture Research), Norway, to carry out the studies. He said, "The data presented here indicate that both production of bone and cartilage were disrupted when promoting fast growth using elevated temperature. It is very likely that higher temperatures result in the increased rate of deformities observed in the 16C group".

The scientists reared 400 fish in 10C water and another 400 at 16C. The fish in the 16C water grew faster, but 28% were found to show some signs of skeletal deformity, in comparison to 8% of the fish reared in the cooler tank. Takle said, "Our results strongly indicate that temperature induced fast growth is severely affecting gene transcription in osteoblasts and chondrocyte bone cells, leading to a change in the tissue structure and composition".

In a second related study, fish with vertebral deformities were studied in detail. Takle said, "The deformity process involves molecular regulation and cellular changes similar to those found in mammalian intervertebral disc degeneration"......... Posted by: Kelly      Read more         Source

July 6, 2010, 7:13 AM CT

Digital embryo gains wings

The researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Gera number of, who 'fathered' the Digital Embryo have now given it wings, creating the Fly Digital Embryo. In work published recently in Nature Methods, they were able to capture fruit fly development on film, and were the first to clearly record how a zebrafish's eyes and midbrain are formed. The improved technique will also help to shed light on processes and organisms, which have so far been under-studied because they could not be followed under a microscope.

"Non-transparent samples like the fruit fly embryo scatter light, so the microscope picks up a mixture of in-focus and out-of-focus signal good and bad information, if you like," says Ernst Stelzer, whose group carried out the project at EMBL. "Our new technique enables us to discriminate between that good and bad information, so it allows us to record organisms which have so far been poorly studied, because of their unfortunate optical properties".

Philipp Keller, who co-led and conducted the work, and Ernst Stelzer overcame the difficulties caused by thick, opaque samples, by shining patterns of light on them, instead of the usual continuous light sheet. This generates an image with alternating light and dark stripes, unless the light bounces off the sample and changes direction, in which case this stripy pattern will be blurred. By taking multiple images of different phases of the light pattern, and combining them, a computer can filter out the effects of scattered light and generate an accurate image of the sample, thus enabling researchers to record images that were previously unobtainable......... Posted by: Kelly      Read more         Source

June 24, 2010, 11:15 PM CT

System that controls sleep

In a novel mathematical model that reproduces sleep patterns for multiple species, an international team of scientists has demonstrated that the neural circuitry that controls the sleep/wake cycle in humans may also control the sleep patterns of 17 different mammalian species. These findings, reported by scientists from Brigham and Women's Hospital (BWH), the University of Sydney, and the Center for Integrated Research and Understanding of Sleep (Camperdown, Australia), suggest that fundamental physiological mechanisms are at work across diverse species, even though sleep patterns vary drastically. This research published June 24th in the open-access journal PLoS Computational Biology.

"These findings show that eventhough mammalian sleep is remarkably diverse in expression, from dolphins who sleep with one brain half at a time to rodents who have a number of short naps, it is very likely universal in origin, which suggests that this simple system is both highly flexible and evolutionarily conserved," said Andrew Phillips, main author of the paper and researcher in the Division of Sleep Medicine at BWH.

Over the past decade, scientists have reported findings correlation to the structures in the brain that are critical to sleep regulation, but these findings have been limited to a small number of species. Until now, it was unclear to what extent these physiological mechanisms are universal across all mammals, particularly given such large interspecies differences in sleep patterns......... Posted by: Kelly      Read more         Source

June 24, 2010, 10:36 PM CT

Even brooding female birds are sensitive to visual stimulation

In a breeding experiment with Houbara bustards - a North African bird species with a very distinctive courtship behaviour, researchers have concluded that visual stimulation from attractive males of the same species positively affects brooding females, improving offspring growth. Females that observed highly displaying male birds in the experiment were more fertile and had a greater breeding success due to an increased allocation of testosterone into their eggs, leading to an increase in the growth rate in chicks. The results showed that using artificial insemination without appropriate stimulation of breeding females probably has negative impacts on their breeding performance and can therefore even affect the survival of a species, as per Adeline Loyau and Frederic Lacroix in the online edition of Proceedings of the Royal Society B

For the experiment, Loyau of the Helmholtz Center for Environmental Research (UFZ) and the French CNRS station for experimental ecology and her colleague Lacroix (ECWP) confronted 90 brooding Houbara bustard females (Chlamydotis undulata undulata) with various individuals of the same species. In the Emirates Center for Wildlife Propagation (ECWP) in Moroccan Missour, 30 female birds were visually confronted with either highly displaying male birds, poorly displaying male birds, or females. During the experiment the female birds under investigation were artificially inseminated and kept isolated in aviaries five meters apart from birds of the same species in other aviaries. That way the researchers were able to exclude any other factors from playing a role in the experiment other than that of visual stimulation. "To my knowledge our study is the first example in species conservation of a successful manipulation of maternal allocation of resources through sensory stimulation ", explains behavioural biologist Adeline Loyau from the UFZ, "Our results show that it is possible to control maternal allocation of resources independent of the quality of male genes." Male display courtship constitutes an effective signal thereby providing conservationists with a simple and inexpensive means. The results could therefore be very significant for the improvement of captive breeding programs of other threatened bird species......... Posted by: Kelly      Read more         Source

June 24, 2010, 10:15 PM CT

3D Models of Whole Mouse Organs

Yale University engineers have for the first time created 3D models of whole intact mouse organs, a feat they accomplished using fluorescence microscopy. The team reports its findings in the May/recent issue of the Journal of Biomedical Optics, as per a research findings published online this week.

Combining an imaging technique called multiphoton microscopy with "optical clearing," which uses a solution that renders tissue transparent, the scientists were able to scan mouse organs and create high-resolution images of the brain, small intestine, large intestine, kidney, lung and testicles. They then created 3D models of the complete organs-a feat that, until now, was only possible by slicing the organs into thin sections or destroying them in the process, a disadvantage if more information about the sample is needed after the fact.

With traditional microscopy, scientists are only able to image tissues up to depths on the order of 300 microns, or about three times the thickness of a human hair. In that process, tissue samples are cut into thin slices, stained with dyes to highlight different structures and cell types, individually imaged, then stacked back together to create 3D models. The Yale team, by contrast, was able to avoid slicing or staining the organs by relying on natural fluorescence generated from the tissue itself......... Posted by: Kelly      Read more         Source

June 14, 2010, 10:08 PM CT

Sequencing the salmon genome

The economically important, environmentally sensitive Atlantic salmon species is one step closer to having its genome fully sequenced, thanks to an international collaboration involving researchers, funding agencies and industry from Canada, Chile and Norway.

Genome BC partnered with the Chilean Economic Development Agency, InnovaChile, Norwegian Research Council, Norwegian Fishery and Aquaculture Industry Research Fund to form the International Cooperation to Sequence the Atlantic Salmon Genome (the Cooperation).

Together they are well underway on a multi-million dollar, multi-phased project that will produce a genome sequence that identifies and maps all of the genes in the Atlantic salmon genome and can act as a reference/guide sequence for the genomes of other salmonids (e.g. Pacific salmon, rainbow trout and more distantly related fish such as smelt and pike.).

Phase one of the project was awarded to Beckman Coulter Genomics to produce a 4X coverage genome using paired-end, plasmid, fosmid and BAC Sanger sequences. It is expected that this phase will be complete in January, 2011.

The Cooperation is gearing up for phase two which will result in a high definition and well-annotated genome using primarily next generation sequencing technologies. The Cooperation is seeking interested parties (publically or privately funded genome sequencing centres, or public/private partnerships) to undertake phase two......... Posted by: Kelly      Read more         Source

June 9, 2010, 11:25 PM CT

Impact of fishing on remote coral reefs

Coral reefs - kaleidoscopes of pink anemones and silver sharks - are the planet's most colorful ecosystems and among its most endangered, say marine scientists.

As global warming raises ocean temperatures, a number of corals blanch and die, a phenomenon called "coral bleaching." And pumping large amounts of carbon dioxide into the atmosphere could make the ocean more acidic, further decimating corals and the fish that depend on them for food and shelter.

Millions of people inhabit coral reefs around the world, putting additional pressure on reef menageries. Establishing sustainable fisheries, even at remote islands and atolls, could significantly slow the decline of a number of reefs, say marine ecologists.

"We know that fishing can dramatically change the composition of a reef ecosystem," said Fiorenza Micheli, a professor of biology at Stanford University's Hopkins Marine Station. "By confronting overfishing immediately, we may increase the resilience of coral reefs to global warming and other threats".

To gain new insights on the ecology of reef fishing, Micheli and a team of Stanford scientists are taking advantage of an ongoing "natural experiment" at two isolated Pacific atolls - Palmyra and Tabuaeran (or Fanning Island) - located about 1,000 miles south of Hawaii. The project is funded by Stanford's Woods Institute for the Environment......... Posted by: Kelly      Read more         Source

May 6, 2010, 6:44 AM CT

Mammal Diversity Patterns

Travel from the tropics to the poles, and you'll notice that the diversity of mammals declines with distance from the equator. Move from lowland to mountains, and you'll see diversity increase as the landscape becomes more varied. Ecologists have proposed various explanations for these well-known "biodiversity gradients," invoking ecological, evolutionary and historical processes.

New findings by University of Michigan scientists John A. Finarelli and Catherine Badgley suggest that the elevational patterns of diversity we see today have appeared, disappeared and reappeared over Earth's history and that these patterns arise from interactions between climate change and mountain building.

The results, published online in the journal Proceedings of the Royal Society B, also have implications for conservation efforts in the face of modern-day global warming, said Finarelli, a visiting assistant professor in the Department of Geological Sciences.

In their study, focused on the Miocene Epoch, which began around 23 million years ago and ended about 5 million years ago, Finarelli and Badgley reviewed diversity for more than 400 rodent species from adjacent regions that differed in geologic history and topography. The geologically "active region," which extends from the Front Range of the Rocky Mountains to the Pacific coast, has experienced several episodes of mountain-building and volcanic activity, and as a result has a topographically complex landscape. In contrast, the relatively flat Great Plains, has been more stable geologically......... Posted by: Kelly      Read more         Source

April 26, 2010, 7:27 PM CT

New monitor lizard discovered

A newly discovered species of monitor lizard, a close relative of the Komodo dragon, was published in the journal Zootaxa this week by a professor at UC Santa Barbara and a researcher from Finland.

Sam Sweet, a professor in the department of Ecology, Evolution and Marine Biology at UCSB, and Valter Weijola, a graduate student at Abo Akademi University in Turku, Finland, are the first to describe the distinctive lizard, which lives in the Moluccan islands of east Indonesia. Sweet is an authority on monitor lizard biology.

The scientific name of this lizard is Varanus obor; its popular names are Torch monitor and Sago monitor. It's called Torch monitor because of its bright orange head with a glossy black body. Obor means torch in Indonesian. It is a close relative of the fruit-eating monitor lizard recently reported from the Philippines. The Torch monitor can grow to nearly four feet in length, and thrives on a diet of small animals and carrion.

The Torch monitor exists only on the small island of Sanana in the western Moluccan islands. A unique aspect of this geographical region is the lack of mammalian predators, which may have given reptiles the space to evolve as the top terrestrial predators and scavengers. Several million years ago, this island was situated near New Guinea, and it is possible that the lizard lives on as a relic from that period. It is the only black monitor in its lineage, and the only monitor species anywhere that has evolved red pigmentation......... Posted by: Kelly      Read more         Source

March 24, 2010, 10:27 AM CT

Petri Sheep

In the winter of 2003, a large herd of bison in an Idaho feedlot was cut in half when a disease outbreak swept through, killing 825 animals.

Two years ago, 19 cattle, most owned by FFA students, died after being shown in Washington's Puyallup State Fair.

In both instances, Washington State University scientists determined the animals died of cancerous catarrhal fever because they had been kept near flocks of sheep, which routinely carry a disease called ovine herpes virus 2. Scientists have known of the disease for decades, but have repeatedly been frustrated in their attempts to grow it in a lab-a major step in developing a vaccine.

So they use the next best thing to a Petri dish: sheep.

USDA and WSU researchers, writing in an upcoming issue of the journal Veterinary Microbiology, say they have propagated the virus in sheep and for the first time identified specific cells where it can replicate. Their discovery opens the door for growing these cells and the virus in a laboratory setting, where they can then begin developing vaccines.

Naomi Taus, main author and veterinary medical officer for the Pullman unit of the USDA's Agricultural Research Service, says she and her colleagues collected secretions from sheep-snot, actually-and aerosolized it to expose other sheep. They then took tissue samples from the sheep and searched for infections by looking for fluorescent markers designed to bind with proteins linked to the virus and certain cell types......... Posted by: Kelly      Read more         Source