October 2, 2007, 9:53 PM CT

Thumb-size microsystem enables cell culture

Integrating silicon microchip technology with a network of tiny fluid channels, some thinner than a human hair, scientists at The Johns Hopkins University have developed a thumb-size micro-incubator to culture living cells for lab tests.

In a recent edition of the journal IEEE Transactions on Biomedical Circuits and Systems, the Johns Hopkins scientists reported that they had successfully used the micro-incubator to culture baby hamster kidney cells over a three-day period. They said their system represents a significant advance over traditional incubation equipment that has been used in biology labs for the past 100 years.

We dont believe anyone has made a system like this that can culture cells over a period of days autonomously, said Jennifer Blain Christen, lead author of the journal article. Once its set up, you can just walk away.

The incubators microchannels, fabricated in soft silicone polymer material, allow scientists to easily insert and guide cells and nutrients during experiments, while the computer-controlled electronics keep the cells at the precise temperature that enables them to multiply and thrive. The tiny incubators transparent design makes it easy to view the cells through a microscope or camera equipment without disrupting the conditions that help the cells to flourish......... Posted by: Janet      Read more         Source

October 2, 2007, 9:49 PM CT

How 'Mother of Thousands' Makes Plantlets

New research shows how the houseplant "mother of thousands" (Kalanchoe diagremontiana) makes the tiny plantlets that drop from the edges of its leaves. Having lost the ability to make viable seeds, the plant has shifted some of the processes that make seeds to the leaves, said Neelima Sinha, professor of plant biology at UC Davis.

A number of plants reproduce by throwing out long shoots or runners that can grow into new plants. But mother of thousands goes further: the plantlets are complete miniature plants that become disconnected from the mother plant's circulatory system and drop off, allowing them to spread rapidly and effectively. The houseplant has lost the ability to make viable seeds and only reproduces through plantlets.

Helena Garcês, a graduate student in Sinha's laboratory, Sinha and his colleagues looked at two genes, STM and LEC, in mother of thousands and close relatives, some of which make seeds instead of plantlets. STM controls shoot growth, while LEC is involved in making seeds.

Expression of STM in leaves was essential for making plantlets. In most plants LEC is expressed in seeds, but mother of thousands' version of the gene, LEC1, was expressed in leaves as well. When the scientists transferred the LEC1 variant into other plants, they were unable to make viable seeds......... Posted by: Erica      Read more         Source

Wed, 03 Oct 2007 02:30:32 GMT

Bringing the best in biological research to the world

An other great example of web-based education. The American Society for Cell Biology has launched a unique project and they feature seminars through the web (so-called webinars). You can download iBioSeminars in QuickTime, mp4, iPodVideo or Powerpoint formats.

iBioSeminars is a freely available library of seminars from outstanding scientists. Our mission is to host lectures that describe on-going research in leading laboratories (they are not basic, survey-style lectures as might be found in undergraduate or graduate student biology courses). However, iBioSeminars features a more extensive introduction into the subject matter than a typical 50 min university seminar. Thus, these lectures are intended to be more accessible than many typical department seminars to advanced undergraduates/beginning graduate students and researchers outside of the specific field. Posted by: Bertalan      Read more     Source

October 1, 2007, 10:13 PM CT

Three-way mating game of North American lizard

An intricate three-way mating struggle first observed in a species of North American lizard has been discovered in a distant relative, the European common lizard. The two species are separated by 5,000 miles and 175 million years of evolution, yet they share behavioral and reproductive details right down to the gaudy colors of the males, as per new research reported in the recent issue of American Naturalist and now available online.

The triangle of competing strategies, which biologists liken to the children's game rock-paper-scissors, may be far more common than previously recognized--and may even shape the way humans behave, as per lead author Barry Sinervo, professor of ecology and evolutionary biology at the University of California, Santa Cruz.

"The models we propose in this paper are a general phenomenon for all animals, humans included," Sinervo said. When faced with the task of gathering food or finding mates, he said, "You either cooperate, or take by force, or take by deception. Those are the three ways you can make a living in any social system. It's one of those basic games that structures life".

Male European common lizards (Lacerta vivipara) adopt one of those three strategies when pursuing females. A quick look at their undersides reveals the strategy: males who sport orange bellies are brutes who invade other lizards' territories to mate with any female they can catch. But while they're gone, drab yellow-bellied males slink onto the vacant territory and mate with unguarded females. White-bellied males guard their mates closely, and cooperate with other white-bellied lizards to keep the yellows at bay. Hence the analogy to rock-paper-scissors: force (orange) defeats cooperation (white), cooperation defeats deception (yellow), and deception defeats force......... Posted by: Kelly      Read more         Source

October 1, 2007, 10:08 PM CT

Amazon Forest Unexpectedly Resilient to Drought

The extensive forests of South America's Amazon are turning out to be tougher than expected when it comes to withstanding the onslaughts of a changing climate. A team of U.S. and Brazilian scientists using the insightful eyes of two NASA satellites has shown that one of the worst droughts in decades could not stop the undisturbed regions of the Amazon forest from "greening up".

The Amazon drought of 2005 reached its peak just as the region's annual dry season was beginning, from July through September. Although the double whammy of the parched conditions might be expected to slow the growth of the forest's leafy canopy, in much of the drought-stricken areas the canopy became significantly greener -- an indication of increased photosynthetic activity.

"Instead of 'hunkering down' during a drought as you might expect, the forest responded positively to drought, at least in the short term," said study author Scott R. Saleska, an assistant professor of ecology and evolutionary biology at the University Of Arizona. "It's a very interesting and surprising response".

The new finding contradicts a prominent global climate model that predicts the Amazon forest would begin to "brown down" after just a month of drought. The model also predicts an eventual forest collapse, shifting the ecosystem permanently from a thick, evergreen, broad-leaved forest to a grassy savanna......... Posted by: Erica      Read more         Source

October 1, 2007, 9:54 PM CT

Genetic differences in clover make one type toxic

That clover necklace you make for your child could well be a ring of poison.

Thats because some clovers have evolved genes that help the plant produce cyanide to protect itself against little herbivores, such as snails, slugs and voles, that eat clover. Other clover plants that do not make cyanide are found in climates with colder temperatures. So, in picking your poison, er, clover, ecology and geography play important roles.

A plant evolutionary biologist at Washington University in St. Louis is trying to get to the bottom of this botanical cloak and dagger tale. Kenneth Olsen, Ph.D., Washington University assistant professor of biology in Arts & Sciences, is looking at the genetics of a wide variety of white clover plants to determine why some plants do and some plants dont make cyanide what biologists call polymorphism, or two types.

We are documenting the effect of natural selection at the DNA sequence level to understand the molecular evolution of this polymorphism, said Olsen. Usually, scientists study model plants such as Arabidopsis or tobacco to understand genetics. But with clover we have a system where we can look in detail at DNA sequence variation and at the same time have a thorough understanding of the plants ecology.

As per a research findings published the week of Sept. 24 in the journal Molecular Ecology, Olsen and colleagues report findings on the molecular basis of the cyanide polymorphism......... Posted by: Erica      Read more         Source

October 1, 2007, 9:30 PM CT

Brain Folding In Higher Mammals

Engineers at Washington University in St. Louis are finding common ground between the shaping of the brain and the heart during embryonic development.

Larry A.Taber, Ph.D., the Dennis and Barbara Kessler Professor of Biomedical Engineering, and Phillip Bayly, Ph.D., Hughes Professor of Mechanical Engineering, are examining mechanical and developmental processes that occur in the folding of the brain's surface, or cortex, which gives the higher mammalian brain more surface area (and hence more intellectual capacity) than a brain of comparable volume with a smooth surface.

Folding is very important in human brain development because some of the worst neurological problems such as schizophrenia, autism and lissenchephaly (smoothness of the cortex, found with severe retardation) are linked to abnormal brain folding. The neuromuscular disorder dystonia is possibly linked to faulty connectivity in the brain, which has been hypothesized to affect cortical folding. The scientists hope that increased understanding of brain folding might someday help prevent such diseases.

Eventhough folding is generally what makes higher mammals smart, Albert Einstein had an abnormally folded brain that resulted in genius. Certain folds in his brain were absent, which might have enabled the area linked to mathematical reasoning to be larger than normal because it didn't have a boundary to restrict its growth......... Posted by: Kelly      Read more         Source

September 27, 2007, 9:40 PM CT

New Species Found In Vietnam

World Wildlife Fund researchers have just announced the discovery of 11 new animal and plant species in a remote area in central Vietnam. They say this underscores the importance of conservation efforts in the ancient tropical forests of the region.

Within the ancient tropical forests of a region known as Vietnam's "Green Corridor," researchers found a snake, five orchids, and two butterflies as well as three other plants new to science and exclusive to the Annamites Mountain Range. Ten other plant species, including four orchids, are still under examination but also appear to be new species.

"Discoveries of so a number of new species are rare and occur only in very special places like the Green Corridor," said Dr. Chris Dickinson, WWF's chief conservation scientist in the Green Corridor. "Several large mammal species were discovered in the 1990s in the same forests so these latest discoveries may be just the tip of the iceberg".

The rainforests of the Central Annamites likely existed as continuous undisturbed forest cover for thousands of years, and, as a result, offer unique habitats for a number of species, said WWF experts.

The new snake species, called the white-lipped keelback, prefers living by streams where it catches frogs and other small animals. With a beautiful yellow-white stripe sweeping along its head and red dots covering its body, the white-lipped keelback can reach 31 inches--almost a yard in length......... Posted by: Janet      Read more         Source

September 27, 2007, 9:37 PM CT

DNA Extracted From Woolly Mammoth Hair

Stephan C. Schuster and Webb Miller of Penn State, working with Thomas Gilbert from Copenhagen and a large international consortium, discovered that hair shafts provide an ideal source of ancient DNA -- a better source than bones and muscle for studying the genome sequences of extinct animals. Their research achievement, described in a paper would be reported in the journal Science on Sept. 28, includes the sequencing of entire mitochondrial genomes from 10 individual woolly mammoths.

Schuster and Miller, working at Penn State's Center for Comparative Genomics and Bioinformatics, and Gilbert, from the Center for Ancient Genetics at the University of Copenhagen, led a team of collaborators that includes a large group of scientists and museum curators from the United States, Russia, Belgium, Denmark, France, Italy, Sweden and the United Kingdom.

The research team obtained hair from 10 woolly mammoths collected from a wide swathe of northern Siberia and with dates of death spanning approximately 38,000 years -- from 50,000 years to 12,000 years ago. Before this study, only seven mitochondrial genomes from extinct animals had been published: four from ancient birds, two from mammoths and one from a mastodon.

"DNA in bones and muscle commonly degrades and becomes contaminated with genetic material from other sources such as bacteria, limiting its usefulness in scientific studies," Schuster explained. Because only a tiny proportion of ancient bones and muscle are preserved in such a way that uncontaminated DNA can be recovered, research with such materials has involved laborious efforts, sometimes spanning as long as six years for a single study. In contrast, Miller said, "Once I get the data from the genome sequencer, it takes only five minutes to assemble the entire mitochondrial genome."........ Posted by: Kelly      Read more         Source

September 27, 2007, 9:23 PM CT

Wasp altruism evolved from maternal behavior

Scientists at the University of Illinois have used an innovative approach to reveal the molecular basis of altruistic behavior in wasps. The research team focused on the expression of behavior-related genes in Polistes metricus paper wasps, a species for which little genetic data was available when the study was begun. Their findings appear today online in Science Express.

Like honey bee workers, wasp workers give up their reproductive capabilities and focus entirely on nurturing their larval siblings, a practice that seems to defy the Darwinian prediction that a successful organism strives, above all else, to reproduce itself. Such behaviors are indicative of a eusocial society, in which some individuals lose, or sacrifice, their reproductive functions and instead work to benefit the larger group.

Behavioral researchers have long noted the similarity between the maternal behaviors of some wasps and the nurturing and provisioning activities of workers. Until now, no study had uncovered a genetic link between the two.

The scientists observed that the pattern of behavior-related genes expressed in the brains of worker wasps was most similar to that seen in foundresses, the female wasps who alone build new colonies and devote much of their early lives to maternal tasks......... Posted by: Kelly      Read more         Source