August 15, 2007, 8:19 PM CT

Humans fostering forest-destroying disease

Enjoying your August vacation? Well, (as they say in the summer movies) theres a killer in the woods. Its strike has been consistently quiet, sudden, and deadly. Unknowingly, we have all been playing into its hands But put down that rock -- you personally are not in any danger. Its the woods themselves that are getting axed and you may be an accomplice.

Melodrama aside, the threat is very serious the killer is an invasive, forest-destroying plant disease known as Sudden Oak Death. Caused by an (apparently) non-native water mold (Phytophthora ramorum), the disease affects a broad range of woody plants, and is especially lethal to our native oaks. In the last few years, it has infected and killed large stands of western oaks with alarming suddenness (hence the name). From its initial California appearance sometime in the mid-1990s, the disease has been spreading rapidly, changing the landscape as it goes.

People tend to not care about plants and forests as much as we do about humans and animals, but sudden oak death could be a bird flu of the plant world waiting to happen, said Ross Meentemeyer, a landscape ecologist at the University of North Carolina at Charlotte. This may be even worse than chestnut blight in its impact on our forests, since it is affecting multiple keystone species......... Posted by: Erica      Read more         Source

August 8, 2007, 9:36 PM CT

New technology reveals seal behavior

New technology has allowed an international team including UK researchers from University of St Andrews and British Antarctic Survey to witness for the first time the behaviour of the southern elephant seal (Mirounga leonina) and how it relates to its physical environment. Small sensors were attached to 85 seals to track their movements and collect data about their marine environment. Results are published this week in the journal Proceedings of the National Academy of Sciences.

The seals were tagged at the islands of South Georgia, Kerguelen and Macquarie in the Southern Ocean, and at the western coast of the Antarctic Peninsula. The data from the seals was transmitted back to land via satellite and shows that elephant seals adopted different strategies to find food.

The Sea Mammal Research Unit at St Andrews University led the research. Author Mike Fedak says, These data are really exciting. This new technology has allowed us to see where the seals go and understand their behaviour in the context of different characteristics of water in the Southern Ocean. The majority of animals from South Georgia fed within the Antarctic Circumpolar Current, but seals from other locations had a very different strategy, and visited colder waters nearer the continental shelf......... Posted by: Kelly      Read more         Source

August 8, 2007, 9:11 PM CT

Differing Patterns Of Rainforest Biodiversity

Rainforests are the worlds treasure houses of biodiversity, but all rainforests are not the same. Biodiversity may be more evenly distributed in some forests than in others and, therefore, may require different management and preservation strategies. That is one of the conclusions of a large-scale Smithsonian study of a lowland rainforest in New Guinea, reported in the Aug. 9 issue of the journal Nature.

Most prior research has focused on diversity hot spots, such as upland rainforests in the foothills of the Andes, where steep gradients in elevation, temperature, rainfall and other environmental factors boost diversity by creating diverse habitats within a short distance. Such change in a regions species makeup between sites is called beta diversity: some rainforests have steep environmental gradients and high beta diversity.

A large proportion of the worlds remaining rainforests are lowland forests in New Guinea, Borneo and the Congo and Amazon Basins. A number of scientists have speculated that such lowland rainforests also would have high beta diversity, but this has not been rigorously tested. Little data exists for species distributions in these vast forests, especially for insects, which make up a large share of the worlds biodiversity.

An international group of entomologists and botanists, including Smithsonian researchers, has assembled data representing 500 species of caterpillars, ambrosia beetles and fruit flies in the undisturbed lowland rainforest of the Sepik and Ramu river basins in Papua New Guinea. The team collected insects and plants from eight study sites across 75,000 square kilometers of contiguous forestan area the size of South Carolinaand noted the variation in species makeup among the different sites......... Posted by: Janet      Read more         Source

August 7, 2007, 10:30 PM CT

tracing genetic history of coconut

The coconut has been popular in lore and on palates for centuries, yet little is known about the history of coconut's domestication and dispersal around the world.

Now, a biologist at Washington University in St. Louis is embarking on the task of understanding the plant's history by exploring the genetics of the coconut (Cocos nucifera L.).

Kenneth Olsen, Ph.D., Washington University assistant professor of biology in Arts & Sciences, has received a $20,000 grant from the National Geographic Society to study the DNA of the plant, which can be used to infer historical relationships among populations. The work will be done in collaboration with Bee Gunn, a research specialist at the Missouri Botanical Garden.

"The coconut played a crucial role in the history of human exploration and dispersal across the tropics, and it continues to play a fundamental role in human societies today," said Olsen. "As a portable source of nutrition and water, the coconut was critical for humans to be able to voyage, establish trade routes, and colonize lands in the Pacific Rim, coastal India, Africa and South America.

"Our preliminary DNA sequence data show genetic variation within the coconut, and this is key to delineating historical relationships among different populations......... Posted by: Erica      Read more         Source

August 6, 2007, 5:28 PM CT

Satellite tracking of penguin travels

You could understand if a half-dozen Magellanic penguins developed a "big bird is watching" phobia before this month is over, but the surveillance really will be for their own good.

University of Washington researchers will attach satellite tracking devices to the backs of six penguins that have been treated at two centers in northern Argentina after their feathers were fouled with oil. The birds will be released into the Atlantic Ocean and their movements traced using satellites and the Internet.

The idea is to plug a critical gap in the knowledge of the Magellanics' annual life cycle, their movements on the journey from their winter feeding grounds back to their breeding colonies along the southern Argentina coast and the Islas Malvinas, or Falkland Islands.

"We're missing that information. We know what happens when they leave the breeding grounds but we don't know what happens on the return trip," said Elizabeth Skewgar, a University of Washington doctoral student in biology.

"We want to model the energy requirements for these birds so that we understand what it takes to return to the breeding grounds and still have enough energy to reproduce. Human fisheries competing for the same food could make migration even more difficult for them"......... Posted by: Kelly      Read more         Source

Sat, 04 Aug 2007 09:10:24 GMT

Molecule of the Month: Anabolic Steroids

Athletes are constantly striving for better performance in their sports. Most athletes stay in top shape through a rigorous training program in fitness and nutrition, giving them the strength and stamina to push their bodies to the physical limit. But some athletes also look to biochemistry to improve their performance even further. There are many ways to give nature an artificial boost. For instance, some athletes artificially increase the number of red blood cells in their blood, either by injecting purified cells or by using the blood-stimulating hormone erythropoietin. The extra red blood cells carry more oxygen to their straining muscles than in normal blood, giving them an edge in endurance. Similarly, many male athletes use steroid hormones like testosterone to spur their muscles into growth far beyond what is normally possible, giving them the edge in strength. These methods are controversial and regarded by many to be unethical, and thus are generally banned from organized sporting events. However, the many drug testing scandals currently in the news show that these methods are still in widespread use.

Anabolic steroids like testosterone are among the most common performance enhancing drugs used by athletes today. Anabolic steroids have two major functions. First, they are androgenic, being responsible for control of “male” characteristics. Before birth, testosterone directs the formation of male characteristics in the growing embryo, and at puberty, raised levels of testosterone direct the changes as a boy grows into a man. Second, these steroids are anabolic: they regulate anabolic processes such as synthesis of protein in muscle, formation of blood cells, and the emotional and physical aspects of sexual function.

More from David Goodsell here. Posted by: PhilipJ      Read more     Source

Sat, 04 Aug 2007 02:33:28 GMT

What I did for the last year.....

I've just returned from the GRC: Microbial Population Biology conference where I presented a poster on my work for the past year. In a few installments I'd like to reproduce this poster here.

My major question of interest was, "How does molecular stochasticity in the individual cell affect major life history traits?" To address this question, I used the enterobacteriophage lambda strain cI857 as a model. Under normal circumstances, cI857 integrates itself into E. coli's genome where it is passed horizontally to daughter cells. Most of the phage's genome is repressed at this point. However, after a temperature spike, the phage is induced into the lytic cycle. Here the "late" genes are expressed, including the lysis cassette and the genes that make phage babies.The lysis cassette contains four genes that produce five proteins. I'll focus just on two: holin and endolysin. The best available model suggests that holin integrates itself into the host's inner membrane. Over time, the holin concentration in the membrane rises, until it spontaneously condenses into a raft. Subsequently the holin undergoes a conformational change producing a hole in the inner membrane. This permits endolysin to attack and degrade the outer membrane, leading to host cell lysis and the release of phage babies into the surrounding medium. Thus holin, and its rate of production, is the main determinant of lysis time, or in life history theory, generation time. The rate of holin production depends on protein translation from low copy mRNA transcripts. Since a single mRNA transcript can produce multiple holin molecules, small changes in mRNA numbers can have large effects on holin production and, hence, the timing of lysis. My project looked at how differences in mRNA production and differences in holin structure led to variability in lysis timing. I'll discuss these in greater detail in a later post and show some of my data.
A cool animation sequence of the lytic cycle is available here.

Lead photo: Maria Schnos, Institute for Molecular Virology, University of Wisconsin, Madison
Genetic Map of the λ genome from CA Reinhart, W. Kentucky University. Figure by me. Posted by: Dennehy      Read more     Source

August 1, 2007, 9:33 PM CT

Makes The Mice Less Fearful

A University of Iowa study shows that loss or chemical inhibition of a protein, known as acid sensing ion channel protein (ASIC1a), reduces innate fear behavior in lab animals, making normally timid mice relatively fearless. The findings might provide useful insight into anxiety disorders and may even point the way to a new therapeutic target.

For humans and other animals, some fears seem to be, in large part, instinctive and inborn rather than learned. For example, laboratory animals fear certain predators even though they have never been exposed to a predator. However, little is known about the brain mechanisms involved in innate fear responses.

The UI study, reported in the scientific journal, Biological Psychiatry, and available online July 30, shows that disrupting the ASIC1a protein alters innate fear reactions in mice and suggests that this protein may be a critical component of the brain systems that underlie innate fear.

The UI team, led by John Wemmie, M.D., Ph.D., assistant professor of psychiatry in the Roy J. and Lucille A. Carver College of Medicine, focused on ASIC1a because earlier research from the lab had shown that the protein was important in learned fear.

The new study examined the protein's role in innate fear by disrupting ASIC1a in mice and observing the effect on several well-studied innate fear behaviors......... Posted by: Kelly      Read more         Source

August 1, 2007, 9:28 PM CT

Plants and stress

Our crops are not doing well these days: too much water, too little sunlight. In short, they are suffering from stress. Researchers from VIB, linked to the Katholieke Universiteit Leuven (K.U.Leuven), have revealed a new mechanism demonstrating the intricate ways in which plants deal with stress. The newly discovered control system has a remarkable way of orchestrating the activity of hundreds of genes, forcing the plant into safety mode; the consumption of energy is contained while the organism is stimulated to mobilize reserves. This may have a negative impact on growth, but it allows the plant to temporarily safeguard itself against pernicious stress conditions. These findings also may prove to be useful beyond the case of plants, for the results are likely to be valuable in understanding disorders such as cancer and diabetes.



Life thanks to plants

Plants catch sunlight and use it as an energy source to produce sugars from CO2 and water. In doing so, they are at the very basis of the food chain. Ultimately, all life on earth depends upon this biochemical process: photosynthesis. Without plants, life as we know it today would simply not be possible. But what if things go wrong" When there is too little sunlight, for example" And what with other stressful conditions for plants" Environmental changes can compromise photosynthesis and exhaust energy supplies......... Posted by: Erica      Read more         Source

August 1, 2007, 9:16 PM CT

Monkeys learn in the same way as humans

Monkeys seem to learn the same way humans do, a new research study indicates.

Like humans, monkeys benefit enormously from being actively involved in learning instead of having information presented to them passively, said Nate Kornell, a UCLA postdoctoral scholar in psychology and lead author of the study, which appears in the recent issue of the journal Psychological Science. The advantage of active learning appears to be a fundamental property of memory in humans and nonhumans alike.

In Kornells study, conducted when he was a psychology graduate student at Columbia University, two rhesus macaque monkeys learned to place five photographs in a particular order. The photographs were displayed on a touch-screen computer monitor similar to those found on ATMs. When the monkeys pressed a correct photograph, a border appeared around it. When either monkey pressed all five photographs in the correct order, he received a food reward. The chance of guessing all five accurately is less than one percent.

In all, each monkey learned to order at least 18 separate series of photographs, which included such items as a fish, a human face, a building, a football field and a flame from a match. They underwent three of training before being tested.

In some of the training trials, the monkeys had to figure out the correct order themselves, while in others, they had the option of getting help by pushing an icon in the corner of the screen that caused the border of the correct photograph to flash. They were rewarded with an M&M candy each time they correctly completed the task without help and with a less desirable food pellet when they completed the task with hints from the help icon. After three days, the monkeys were tested without the benefit of the help icon......... Posted by: Kelly      Read more         Source