July 17, 2007, 10:26 PM CT

Monkeys don't go for easy pickings

Animals' natural foraging decisions give an insight into their cognitive abilities, and primates do not automatically choose the easy option. Instead, they appear to decide where to feed based on the quality of the resources available and the effect on their social group, rather than simply selecting the nearest food available. These findings¹ by Elena Cunningham and Charles Janson, respectively from the New York University College of Dentistry and the State University of New York, have just been published in a special issue of the journal Animal Cognition². The articles in the issue look at the interaction of social and ecological factors and their influence on the evolution of primate intelligence.

The authors investigated whether a group of six white-faced saki monkeys, living on an island in Venezuela, used memory to travel to select feeding resources during a period of fruit abundance. The study looked at the resources available to the sakis and compared the observed distances traveled with predicted distances, using a combination of statistical analyses and computer models.

The monkeys' daily foraging pattern consisted of frequent short feeding bouts and a few long feeding bouts. Surprisingly, the sakis traveled four times further than the predicted distances, suggesting that the sakis were extremely selective about the food they ate. The sakis preferred trees with abundant fruit and trees with water holes. When fruiting trees were abundant, the sakis traveled efficiently to the trees with the most fruit, ignoring closer, less productive ones......... Posted by: Kelly      Read more         Source

July 17, 2007, 10:17 PM CT

Sequencing method yields fuller picture

University of Southern California biologists have developed a method for sequencing both chromosomes of an organism.

Their study appears in a recent issue of Genome Research.

The statistical method is significant because when scientists announce they have sequenced an organisms genome, they really mean that they have created a mosaic of two chromosomes, said USC computational biologist Lei Li.

A mosaic means its not real, Li said.

Lead author and former graduate student Jong Hyun Kim, advised by Li and USC University Professor Michael Waterman, was able to infer a complete sequence of the chromosomes of Ciona intestinalis, a marine invertebrate, from existing sequencing data.

Kims method exploited the high rate of genetic mutations in the organism. Other organisms with high genetic variability, such as certain fish, also may be suitable.

Because the human genome has a relatively low mutation rate, the method cannot be applied to people.

However, Kim said, the method might be useful in sequencing parts of the human genome that display high variability.

As a by-product of their analysis, the scientists added to growing evidence that so-called junk DNA may have a function after all.

Recent studies have shown that junk DNA expresses proteins which may regulate gene function, and that sections of junk DNA have been highly conserved during evolution, suggesting that they play an important role......... Posted by: Janet      Read more         Source

July 17, 2007, 10:17 PM CT

Foxes get frisky in the far north

Bees do it, chimps do it Now it seems Arctic foxes do it, too. New research looking at the DNA fingerprints of canids in the Far North has revealed that foxes once believed to be monogamous are in fact quite frisky.

From polyandry to multiple paternity and plural breeding, Canadian scientists have gathered DNA evidence from adult foxes and their offspring that proves that some arctic foxes are mixing it up when it comes to mating.

Until recently, wildlife biologists considered a number of species of caninesincluding foxes, wolves and coyotesto be monogamous. But molecular genetic techniques are starting to reveal complexities in mammalian mating systems that were not apparent from findings based on observation of animal social behavior. Using a technique called microsatellite DNA fingerprinting, a team of scientists from the University of Alberta in Edmonton and the University of Quebec at Rimouski collected DNA samples from 49 arctic foxes trapped in dens on Bylot Island, Nunavut.

In three-quarters of the dens, DNA fingerprints showed that the fox cubs were the offspring of a single male and female. But in a quarter of the cases, the arctic foxes proved to be less exclusive, with one litter providing the first genetic evidence of polyandry (females having multiple male mates at one time) with multiple paternity......... Posted by: Kelly      Read more         Source

July 16, 2007, 10:08 PM CT

Vaccine trials for koala

The first Australian trials of a vaccine developed by Queensland University of Technology that could save Australia's iconic koala from contracting chlamydia are planned to begin later this year.

Professor Peter Timms, from QUT's Institute of Health and Biomedical Innovation, said chlamydia was a major threat to the continued survival of koalas with almost all populations affected by the disease.

"The trial is planned to begin before the end of the year and will test the vaccine's ability to induce a good immune response in the koala against chlamydia," he said.

"Assuming that this first trial is successful, then future trials can determine if this immune response is able to protect the koalas against chlamydial disease.

"We've been able to develop the vaccine for koalas as a result of our studies on the development of human chlamydial vaccines done in the mouse model. We have identified several novel vaccine proteins that we hope will protect koalas as well."

Professor Timms said chlamydia in koalas was a significant cause of infertility, urinary tract infections, and inflammation in the lining of the eye that often led to blindness.

"The numbers of koalas with chlamydia seems to be increasing," he said.

"As much as 40-50 per cent of koalas coming into care in both Queensland and NSW are showing clinical signs of the disease and it seems to be getting worse"......... Posted by: Kelly      Read more         Source

July 14, 2007, 8:14 AM CT

Please Touch the Animals

There is nothing like making a physical contact with the animals you love. A touch and physical contact brings a special relationship between human and the animal.

A lighter touch by the zookeepers keepers keep their animals strong and healthy. Zoo keepers in Oakland Zoo use this touch technique to the next dimension. They use various techniques like body work and acupuncture for giraffes, to pachyderm pedicures. See how the Oakland Zoo is using alternative therapys to guarantee the well-being of its residents......... Posted by: Kelly      Read more

July 12, 2007, 10:39 PM CT

Electrified cells don't get dizzy

One might believe that flies are mainly annoying. However, taking a closer look quickly reveals that flies are amazing flight artists. The house fly, for example, races with two meters per second through the room, only to land with half a backward roll on the ceiling. In contrast to humans, the fly can't move its eyes and has to move its head or whole body to keep the environment in view. The correct detection and differentiation of optical input - how and where to does it fly, or is an enemy approaching - seem quite complex for the comparatively small fly brain. The more amazing is that the central flight control centre in the fly's brain needs only 60 nerve cells for these complex tasks. Alexander Borst and his group at the Max-Planck-Institute of Neurobiology investigate just how these cells accomplish this.

In cooperation with two colleagues from London and Jerusalem, the researchers focused on a subset of ten cells. These so-called VS-cells enable the fly to detect rotational axes. When a fly rotates its body around an axis, the environment passes its eyes in the opposite direction. To process this information, the VS-cells have a parallel arrangement, and each cell receives its information only from a small vertical column in the eye. In this way VS1 "sees" a small column in front of the fly, VS5 to the side and VS10 in the hind part of the eye......... Posted by: Janet      Read more         Source

July 12, 2007, 10:36 PM CT

A small leak will sink a great ship

Flowers of higher plants are built in a similar pattern: their outermost whorl is composed of sepals, which protect the young bud, thereafter comes a whorl of often colorful petals attracting insect pollinators, followed by a whorl of stamens with pollen sacks and the innermost whorl holds carpels, which later give rise to the fruit and seeds. This basic architecture is comparable in higher plants prompting the question after common components of a genetic 'masterplan'.

Researchers in the group of Zsuzsanna Schwarz-Sommer investigated a mutant of snapdragon where stamens form instead of petals (Fig. 1). Interestingly, a strikingly similar mutant occurs in another plant species, in Petunia. 'We already suspected some ten years ago when we first looked at these mutants that in the two species a similar defect might disturb the genetic control resulting in the 'wrong organ at the wrong place' explains Mrs. Schwarz-Sommer. A similar example is well known in the fruit fly where a mutant carries a pair of legs at the head instead of the two antennae.

Indeed, experiments performed by the German and Dutch researchers showed that in the two plant species mutation in the same gene conferred altered identity to the floral organs. This gene turned out to code for a microRNA, a small ribonucleic acid consisting of little more than 20 nucleotides. MicroRNAs can recognize and bind to complementary sequences present in messenger RNAs (mRNA) and prevent thereby translation of the mRNA into a protein: the respective gene falls silent. By this interaction microRNAs can influence whole chains of control events......... Posted by: Erica      Read more         Source

July 12, 2007, 10:10 PM CT

Simulated crop provides answer to irrigation issues

outh Asia has witnessed a rapid growth in rice and wheat production that has defined the Green Revolution there. During the past 30 years, the Indian Punjab has transformed its agriculture through new technology that provides for high-producing plants, increased fertilization, and irrigation. Rice and wheat production has more than doubled with an increase in farmed areas, totaling about 6.4 million acres of rice and 8.4 million acres of wheat.

While the Indian Punjabs agricultural performance continues to be impressive, evidence suggests that its coming at a price: their groundwater use is becoming increasingly dangerous to the environment. In some areas, the water quality is worsening as water tables decline. In other areas, water is flooding the soil making it difficult for plant growth. The rampant use of irrigation is encouraged by cheap water policies that provide producers with little or no expense for water use.

Since irrigation water charges are extremely cheap, farmers seem to use it more excessively and inefficiently. They are able to raise crop yields but at the cost of extremely low water quality. It is used this way due to crop decisions farmers must make for their crops before knowing the weather conditions for the upcoming season. Irrigation provides a way around these weather misjudgments. Farmers can adjust the amount of water coming to their crops by irrigation to supplement the precipitation levels......... Posted by: Erica      Read more         Source

July 12, 2007, 8:45 PM CT

Semiconductor Membrane Mimics Biological Behavior

A semiconductor membrane designed by researchers at the University of Illinois could offer more flexibility and better electrical performance than biological membranes. Built from thin silicon layers doped with different impurities, the solid-state membrane also could be used in applications such as single-molecule detection, protein filtering and DNA sequencing.

“By creating nanopores in the membrane, we can use the membrane to separate charged species or regulate the flow of charged molecules and ions, thereby mimicking the operation of biological ion channels,” said lead researcher Jean-Pierre Leburton, the Stillman Professor of Electrical and Computer Engineering at Illinois.

Leburton, with postdoctoral research associate Maria Gracheva and graduate student Julien Vidal, simulated the operation of the semiconductor membrane at a number of electrostatic potentials. They report their findings in a paper accepted for publication in the journal Nano Letters, and posted on the journal’s Web site.

In the researchers’ model, the nanopore-membrane structure is made of two layers of silicon, each 12 nanometers thick, with opposite (n- and p-) doping. The electrostatic potential is positive on the n-side and negative on the p-side of the membrane.

The nanopore has an hourglass shape, with a neck 1 nanometer in diameter and openings on each side of the membrane 6 nanometers in diameter. The “size” of the nanopore can be changed by changing the electrostatic potential around it......... Posted by: Janet      Read more         Source

July 12, 2007, 8:12 PM CT

Unraveling the physics of DNA's double helix

Scientists at Duke University's Pratt School of Engineering have uncovered a missing link in scientists' understanding of the physical forces that give DNA its famous double helix shape.

"The stability of DNA is so fundamental to life that it's important to understand all factors," said Piotr Marszalek, a professor of mechanical engineering and materials sciences at Duke. "If you want to create accurate models of DNA to study its interaction with proteins or drugs, for example, you need to understand the basic physics of the molecule. For that, you need solid measurements of the forces that stabilize DNA".

As per a research findings published online by Physical Review Letters on July 5, Marszalek's team reports the first direct measurements of the forces within single strands of DNA that wind around each other in pairs to form the complete, double-stranded molecules. The work was supported by the National Science Foundation and the National Institutes of Health.

Each DNA strand includes a sugar and phosphate "backbone" attached to one of four bases, which encode genetic sequences. The strength of the interactions within individual strands comes largely from the chemical attraction between the stacked bases. But the integrity of double-stranded DNA depends on both the stacking forces between base units along the length of the double helix and on the pairing forces between complementary bases, which form the rungs of the twisted ladder......... Posted by: Janet      Read more         Source