October 19, 2007, 5:09 AM CT

Researchers studying how singing bats communicate

Bats are the most vocal mammals other than humans, and understanding how they communicate during their nocturnal outings could lead to better therapys for human speech disorders, say scientists at Texas A&M University.

Thousands of bats native to Central Texas fly overhead each night singing songs of complex syllables but at frequencies too high for humans to hear.

Texas A&M researcher Michael Smotherman is trying to understand how Mexican Freetail bats organize syllables into songs and how their communication is associated with the brain. If we can identify those areas in a bat brain [responsible for communication], we can learn more about how a normal [human] brain generates and orchestrates complex communication sequences, Smotherman says. And by understanding how that works, we can then come up with testable hypotheses about what might be going on in speech disorders.

The scientists in Smothermans lab are studying two aspects of bat communication. In behavioral studies, they examine sex differences and seasonal variations in communication, and in physiology studies they try to locate the parts of the bat brain active during communication.

Mexican Freetail bats sing mostly in ultrasonic frequencies that are right above the upper limit of human hearing. Humans can sometimes hear little bits of bat songs, however, when parts of syllables drop low enough......... Posted by: Kelly      Read more         Source

October 17, 2007, 9:35 PM CT

Sea cucumbers fast track organ regrowth

Sea cucumbers are the champions of organ regrowth because they direct their wound healing abilities towards restoring their organs, as per research reported in the online open access journal, BMC Developmental Biology. The discovery that Holothuria glaberrima uses similar cellular mechanisms during wound healing and organ regeneration gives us the opportunity to discover how to repair our own wounds and, perhaps eventually, how to regenerate body parts.

The research was carried out by the researchers Jos San Miguel-Ruiz and Jos Garca-Arrars, at the University of Puerto Rico. "Sea cucumbers should be viewed as the tissue regeneration equivalent of the squid for our knowledge of nerves and Drosophila for genes and the genome. They can help us learn to fix ourselves," commented Professor Garcia-Arraras. "A number of people, including scientists, regard sea cucumbers and other echinoderms like star fish and brittle stars as bizarre, exceptional outcasts because of their regenerative abilities. But we've shown that they use the same 'ordinary' mechanisms and processes to both regenerate and heal wounds".

All animals possess some kind of tissue repair mechanism. The sea cucumber, H. glaberrima, belongs to a group of marine animals that are well known for their ability to regenerate, along with the axolotl salamander, which is also famous for regrowing lost limbs. The researchers made observations over a four-week healing period and observed that sea cucumbers healed up rapidly after receiving a 3 to 5 millimetre cut along the body wall. The repair process involved special cells called morula cells moving to the injury site and full repair was achieved after just a couple of weeks. The cellular events observed during the healing of sea cucumber muscular, nervous and dermal tissues that correspond to those observed during intestinal regeneration include extracellular matrix remodeling and the dedifferentiation of muscle cells......... Posted by: Kelly      Read more         Source

October 17, 2007, 9:02 PM CT

Call for increased focus on production

The worlds major rice-producing nations including China and India are calling for closer collaboration in efforts to feed Asias billions of rice consumers in the face of unprecedented new challenges.

Rice production, which helps feed almost half the world, has been under increasingly intense pressure lately, causing rising consumer prices in a number of Asian nations. Climate change, biofuels, water scarcity, and farmers diversifying into other crops are just some of the factors affecting Asias ability to produce the rice it needs.

The eleventh annual meeting of the Council for Partnerships on Rice Research in Asia (CORRA) last month in month in Vietnam was warned that more must be done to accelerate the development and dissemination of rice varieties to help farmers keep up with production demands. CORRA brings together the senior research representatives of 16 major rice-producing and -consuming nations to highlight and discuss the main issues and challenges facing the Asian rice industry.

The rice-producing nations of Asia are facing a number of of the same challenges in producing the rice they need, so it makes sense for us to work together to overcome these problems, Mangala Rai, the CORRA chair, told the meeting. Dr. Rai is also the chairman and secretary of Indias Department of Agricultural Research and Education (DARE) and director general of the Indian Council of Agricultural Research (ICAR)......... Posted by: Erica      Read more         Source

October 17, 2007, 8:26 PM CT

Human sensitivity to biological motion

Humans may not be any more sensitive in detecting biological motion compared with nonbiological motion, concludes a study recently published in Journal of Vision, an online, free-access publication of the Association for Research in Vision and Ophthalmology (ARVO).

Dr Eric Hiris of St. Mary's College of Maryland, (St Mary's City, MD, US) contends that eventhough a number of papers on the subject begin with statements to the effect that humans are especially sensitive in detecting point-light biological motion, little research has been performed that supports this.

Prior research in this area, as per Hiris, generally has failed to take into account form information in biological motion and/or has used masks that were less than optimal for biological motion.

Using point-light displays, Hiris's study, described in "Detection of biological and nonbiological motion," (http://www.journalofvision.org/7/12/4/) compared biological motion to nonbiological motion with and without an underlying form; equated the effectiveness of masks across displays; and presented targets of various sizes within a constant-sized mask area to determine if mask density predicted detection performance.

Hiris concludes that the resulting evidence does not show that humans are better able to detect biological motion if nonbiological motion contains an underlying form, and, in some cases, even if it does not......... Posted by: Janet      Read more         Source

October 17, 2007, 4:44 AM CT

City Is An Old Growth Forest For Big Owls

It may be news to its bankers, but Charlotte, the biggest city in North Carolina and a major center of the American financial industry, is actually an old growth forest.

At least thats the way the barred owls see it.

Charlotte is famous for having two kinds of green. It is home to two of the nations largest banks and its downtown residential neighborhoods and near-suburbs are also known for their lush yards and green streets, lined with large trees. Less well-known is the fact that the city is almost as well populated with large owls especially barred owls as it is with bankers. Harry Potter would feel very much at home.

In fact, the barred owl population in Charlotte is so strong that the city was chosen to be the site for the most extensive barred owl research study that has ever been attempted, with fieldwork going on in the manicured front lawns and gardened back yards of urban and suburban neighborhoods.

Urban wildlife numbers have been increasing in recent decades, notably in populations of squirrels, Canada geese, raccoons and deer, but the appearance of significant urban populations of barred owls, the third largest owl species in the US, is a surprise to a number of biologists.

If you read about barred owls in the textbooks, it says they need large stands of old-growth forest to survive, notes University of North Carolina at Charlotte ecologist and ornithologist Rob Bierregaard, who has directed the six-year-old research study. Either the barred owls in Charlotte havent read that book or the book is wrong, because they are really here and apparently doing quite well......... Posted by: Kelly      Read more         Source

October 17, 2007, 4:34 AM CT

How basil gets its zing

The blend of aromatic essential oils that gives fresh basil leaves their characteristic warm and sweet aroma is well characterized but not much is known about the enzymatic machinery manufacturing the odiferous mix. Scientists at the Salk Institute for Biological Studies and the University of Michigan followed their noses and solved part of the molecular puzzle.

Their study, reported in the Oct. 4 issue of the journal PLoS ONE, provides a three-dimensional snapshot of the enzyme basil Eugenol Synthase frozen in mid-action as it produces eugenol, the fragrant molecule responsible for basil's spicy overtones reminiscent of cloves and cinnamon.

"This particular enzyme is very interesting since it belongs to a large family of enzymes that perform what we call 'household reactions' but, through evolutionary selection, acquired an additional and completely new function," says Howard Hughes Medical Institute investigator Joseph P. Noel, Ph.D, director of the Jack H. Skirball Center for Chemical Biology and Proteomics, who led the study.

"Eugenol Synthase takes a basic building block that is commonly employed to make wood and turns it into something that is almost the complete opposite of wood - a volatile molecule that easily becomes airborne, is highly aromatic and possesses antimicrobial and pain-dulling properties," marvels Noel......... Posted by: Erica      Read more         Source

October 16, 2007, 7:24 PM CT

The dawn of animal vision

The findings appear in this weeks issue of the scientific journal PLoS ONE. The researchers studied the aquatic animal Hydra, a member of Cnidaria, which are animals that have existed for hundreds of millions of years. The authors are the first researchers to look at light-receptive genes in cnidarians, an ancient class of animals that includes corals, jellyfish, and sea anemones.

Not only are we the first to analyze these vision genes (opsins) in these early animals, but because we dont find them in earlier evolving animals like sponges, we can put a date on the evolution of light sensitivity in animals, said David C. Plachetzki, first author and a graduate student at UC Santa Barbara. The research was conducted with a National Science Foundation dissertation improvement grant.

We now have a time frame for the evolution of animal light sensitivity. We know its precursors existed roughly 600 million years ago, said Plachetzki.

Senior author Todd H. Oakley, assistant professor of biology at UCSB, explained that there are only a handful of cases where researchers have documented the very specific mutational events that have given rise to new features during evolution.

Oakley said that anti-evolutionists often argue that mutations, which are essential for evolution, can only eliminate traits and cannot produce new features. He goes on to......... Posted by: Kelly      Read more         Source

October 12, 2007, 5:07 AM CT

A tiny pinch from a 'z-ring' helps bacteria cells divide

In process that is shrouded in mystery, rod-shaped bacteria reproduce by splitting themselves in two. By applying advanced mathematics to laboratory data, a team led by Johns Hopkins scientists has solved a small but important part of this reproductive puzzle.

The findings apply to highly common rod-shaped bacteria such as E. coli, found in the human digestive tract. When these single-celled microbes set out to multiply, a signal from an unknown source causes a little-understood structure called a Z-ring to tighten like a rubber band around each bacteriums midsection. The Z-ring pinches the rod-like body into two microbial sausages that finally split apart. To shed light on this process, the Johns Hopkins-led team developed a mathematical tool that computed the mechanical force exerted by the Z-ring when it helps these cells split.

The calculation will aid researchers who are trying to learn more about how these microbes live and reproduce. The work also may hasten the development of a new type of antibiotic that could disable the Z-ring to keep harmful bacteria in check.

The bacteria research was published in the Oct. 9 edition of Proceedings of the National Academy of Sciences. The work was led by Sean X. Sun, an assistant professor of mechanical engineering in Johns Hopkins Whiting School of Engineering......... Posted by: Janet      Read more         Source

October 11, 2007, 10:55 PM CT

Stem cell nuclei are soft 'hard drives,'

Scientists pulled cell nuclei into microscopic glass tubes under controlled pressures and visualized the shear of the DNA and associated proteins by fluorescence microscopy. The study showed that nuclei in human embryonic stem cells were the most deformable, followed by hematopoietic stem cells, HSCs, that generate a wide range of blood and tissue cells. Both types of stem cells lack lamins A and C, two filamentous proteins that interact to stabilize the inner lining of the nucleus of most tissue cells. Lamins A and C stiffen cell nuclei and are expressed in cells only after gastrulation, when most stem cells generate the specific tissues of complex organisms.

The fluid-like character of the nucleus is shown to be set largely by the DNA and the DNA-attached proteins that form chromatin. The extent of deformation of the nucleus is further modulated by the lamina.

Understanding the sensitivity of stem cells and their nuclei to external stresses has very practical implications in handling these cells as well as in technologies such as cloning in which nuclei are manipulated, said Dennis Discher, a professor in Penns School of Engineering and Applied Science and the Penn School of Medicines Cell and Molecular Biology Graduate Group.

The study, reported in the Oct. 2 issue of the Proceedings of the National Academy of Sciences, supports the theory that lamin proteins are responsible for much of the genomic lock-down within differentiated cells. Differentiated cells, typified by muscle cells, fat cells and bone cells, all arise from stem cells that have committed to these specialized cell types by locking the DNA into a set pattern of gene expression......... Posted by: Janet      Read more         Source

October 11, 2007, 10:33 PM CT

'Chlamy' genome holds clues

University of Minnesota scientists contributed to a national effort to sequence the genome of an ancient, one-celled organism that will help advance research in a broad range of areas, from biofuels to restoring the environment to understanding a variety of human diseases.

The organism, Chlamydomonas reinhardtii, known affectionately as Chlamy, has long fascinated researchers because it is an ancestor of plants and animals that retains characteristics of both. Like green plants, Chlamy (a type of green alga) uses photosynthesis to convert solar energy and carbon dioxide into biomass. And like a number of animal cells, including human sperm, it has flagella that allow it to swim.

Analysis of the 15,000 genes that make up Chlamys genome revealed hundreds that control photosynthesis and the function of flagella. The genome also provides a glimpse back through time to when all plants and animals were unicellular and used flagella to swim. When they became multicellular, plants put down roots and lost their flagella while animals retained flagella on certain kinds of cells, including sperm and cilia on some cells in the lungs, kidneys and eyes.

Led by the U.S. Department of Energys Joint Genome Institute, the University of California and the Carnegie Institute, the genome study is reported in the Oct. 12 issue of Science......... Posted by: Janet      Read more         Source