April 10, 2008, 9:16 PM CT

Flowers' fragrance diminished by air pollution

Air pollution from power plants and automobiles is destroying the fragrance of flowers and thereby inhibiting the ability of pollinating insects to follow scent trails to their source, a new University of Virginia study indicates. This could partially explain why wild populations of some pollinators, especially bees which need nectar for food are declining in several areas of the world, including California and the Netherlands.

The study appears online in the journal Atmospheric Environment.

"The scent molecules produced by flowers in a less polluted environment, such as in the 1800s, could travel for roughly 1,000 to 1,200 meters; but in today's polluted environment downwind of major cites, they may travel only 200 to 300 meters," said Jose D. Fuentes, a professor of environmental sciences at the University of Virginia and a co-author of the study. "This makes it increasingly difficult for pollinators to locate the flowers".

The result, potentially, is a vicious cycle where pollinators struggle to find enough food to sustain their populations, and populations of flowering plants, in turn, do not get pollinated sufficiently to proliferate and diversify.

Other studies, as well as the actual experience of farmers, have shown that populations of bees, especially bumblebees, and butterflies have declined greatly in recent years. Fuentes and his team of U.Va. researchers, including Quinn McFrederick and James Kathilankal, think that air pollution, particularly during the peak period of summer, may be a factor......... Posted by: Erica      Read more         Source

April 10, 2008, 8:09 PM CT

And the First Animal on Earth Was a ....

A new study mapping the evolutionary history of animals indicates that Earth's first animal--a mysterious creature whose characteristics can only be inferred from fossils and studies of living animals--was probably significantly more complex than previously believed.

The study, which was funded by the National Science Foundation (NSF), is the cover story of the April 10, 2008 issue of Nature Using new high-powered technologies for analyzing massive volumes of genetic data, the study defined the earliest splits at the base of the animal tree of life. The tree of life is a hierarchical representation of the evolutionary relationships between species that was introduced by Charles Darwin. (See diagram.

Shaking Up the Tree of Life

Among the study's surprising findings is that the comb jelly split off from other animals and diverged onto its own evolutionary path before the sponge. This finding challenges the traditional view of the base of the tree of life, which honored the lowly sponge as the earliest diverging animal. "This was a complete shocker," says Dunn. "So shocking that we initially thought something had gone very wrong.".

But even after Dunn's team checked and rechecked their results and added more data to their study, their results still suggested that the comb jelly, which has tissues and a nervous system, split off from other animals before the tissue-less, nerve-less sponge......... Posted by: Kelly      Read more         Source

April 9, 2008, 8:47 PM CT

Novel 'gene toggles' in world's top food crop

University of Delaware researchers, in collaboration with U.S. and international colleagues, have found a new type of molecule--a kind of "micro-switch"--that can turn off genes in rice, which is the primary source of food for more than half the world's population. The discovery is published in the March 25 issue of the Proceedings of the National Academy of Sciences of the United States of America.

Composed of short lengths of ribonucleic acids (RNAs), on the order of about 20 nucleotides long, these novel molecules, called natural antisense microRNAs (nat-miRNAs), target the genes sitting directly across from them on the opposite strand of DNA in a rice cell.

In addition to uncovering a new genetic switch and gaining insight about its pathways and evolution, which are important to the health of a grain that feeds most of the world, the research also may help researchers locate this type of novel gene regulator in other organisms, including humans. MicroRNAs regulate 30 percent of human genes and thus are critical to human health and development.

The research was led by Pamela Green, the Crawford Greenewalt Chair of Plant Sciences at UD, and Blake Meyers, associate professor of plant and soil sciences, and their laboratory groups at the Delaware Biotechnology Institute, including associate scientist Cheng Lu, postdoctoral scientists Dong-Hoon Jeong and Kan Nobuta, graduate students Karthik Kulkarni, Manoj Pillay, and Shawn Thatcher and research associate Rana German......... Posted by: Erica      Read more         Source

Thu, 10 Apr 2008 02:23:14 GMT

Trippy translation

I’m taking a class on the chemistry of biological systems this term (part of the reason why it has been relatively quiet around here recently). A large section of the course was on the details of protein synthesis, or how the ribosome takes mRNA and turns it into protein. Somehow this film was never shown in class, where a (literal) interpretation of the molecular dance is depicted:

Directed in 1971 by Robert Alan Weiss for the Department of Chemistry of Stanford University and imprinted with the “free love” aura of the period, this short film continues to be shown in biology class today. It has since spawn a series of similar funny attempts at vulgarizing protein synthesis. Narrated by Paul Berg, 1980 Nobel prize for Chemistry. Called “A Protein Primer”, the film is surprisingly accurate given that it was produced in the 70s. The dance starts around the 3:30 mark. Enjoy!

(Hat tip: Kottke) Posted by: PhilipJ      Read more     Source

April 8, 2008, 10:06 PM CT

Don't harm microbes that clean the environment

Even large amounts of manufactured nanoparticles, also known as Buckyballs, don't faze microscopic organisms that are charged with cleaning up the environment, as per Purdue University researchers.

In the first published study to examine Buckyball toxicity on microbes that break down organic substances in wastewater, the researchers used an amount of the nanoparticles on the microbes that was equivalent to pouring 10 pounds of talcum powder on a person. Because high amounts of even normally safe compounds, such as talcum powder, can be toxic, the microbes' resiliency to high Buckyball levels was an important finding, the Purdue researchers said.

The experiment on Buckyballs, which are carbon molecules C60, also led the researchers to develop a better method to determine the impact of nanoparticles on the microbial community.

"It's important to look at the entire microbial community when nanomaterials are introduced because the microbes are all interdependent for survival and growth," said Leila Nyberg, a doctoral student in the School of Civil Engineering and the study's lead author. "If we see a minor change in these microorganisms it could negatively impact ecosystems."

The microbes used in the study live without oxygen and also exist in subsurface soil and the stomachs of ruminant animals, such as cows and goats, where they aid digestion......... Posted by: Janet      Read more         Source

April 8, 2008, 9:56 PM CT

Fingerprint of Evolution Across the Human Genome

The Human Genome Project revealed that only a small fraction of the 3 billion "letter" DNA code actually instructs cells to manufacture proteins, the workhorses of most life processes. This has raised the question of what the remaining part of the human genome does. How much of the rest performs other biological functions, and how much is merely residue of previous genetic events? .

Researchers from Cold Spring Harbor Laboratory (CSHL) and the University of Chicago now report that one of the steps in turning genetic information into proteins leaves genetic fingerprints, even on regions of the DNA that are not involved in coding for the final protein. They estimate that such fingerprints affect at least a third of the genome, suggesting that while most DNA does not code for proteins, much of it is nonetheless biologically important - important enough, that is, to persist during evolution.

Conservation of genetic information.

To gauge how critical a particular stretch of DNA is, biologists often look at the detailed sequence of "letters" it consists of, and compare it with a corresponding stretch in related creatures like mice. If the stretch serves no purpose, the thinking goes, the two sequences will differ because of numerous mutations since the two species last shared an ancestor. In contrast, it's believed that the sequences of important genes will be similar, or "conserved," in different species, because animals with mutations in these genes did not survive. Biologists therefore regard conserved sequences as a sign of biological importance......... Posted by: Janet      Read more         Source

April 6, 2008, 8:40 PM CT

Meteorites delivered the 'seeds' of Earth's left-hand life

Flash back three or four billion years Earth is a hot, dry and lifeless place. All is still. Without warning, a meteor slams into the desert plains at over ten thousand miles per hour. With it, this violent collision may have planted the chemical seeds of life on Earth.

Researchers presented evidence today that desert heat, a little water, and meteorite impacts may have been enough to cook up one of the first prerequisites for life: The dominance of left-handed amino acids, the building blocks of life on this planet.

In a report at the 235th national meeting of the American Chemical Society, Ronald Breslow, Ph.D., University Professor, Columbia University, and former ACS President, described how our amino acid signature came from outer space.

Chains of amino acids make up the protein found in people, plants, and all other forms of life on Earth. There are two orientations of amino acids, left and right, which mirror each other in the same way your hands do. This is known as chirality. In order for life to arise, proteins must contain only one chiral form of amino acids, left or right, Breslow noted.

If you mix up chirality, a proteins properties change enormously. Life couldnt operate with just random mixtures of stuff, he said.

With the exception of a few right-handed amino acid-based bacteria, left-handed L-amino acids dominate on earth. The Columbia University chemistry professor said that amino acids delivered to Earth by meteorite bombardments left us with those left-handed protein units......... Posted by: Janet      Read more         Source

Sun, 06 Apr 2008 13:39:51 GMT

Flour Beetle Genome Sequenced

An international team of researchers has sequenced the genome from the red flour beetle Tribolium castaneum, making it the first beetle and the first insect pest, whose genome has been sequenced. A large international research consortium consisting of 64 research groups from 14 countries with the participation of a research team around Professor Cornelis Grimmelikhuijzen has now sequenced the genome from Tribolium. This genome consists of about 200 million nucleotides (DNA building blocks) that code for about 16,000 genes (or 16,000 proteins). These sequencing efforts are extremely important for agriculture and will enable the development of new methods for the protection of food plants against beetles. The findings have been published in Nature (pdf version available for download ). Posted by: ruth      Read more     Source

April 3, 2008, 8:44 PM CT

The voyage to America

Professor Eske Willerslev was surprised by the results of the DNA tests conducted by himself and his colleagues on samples of what turned out to be fossilised human faeces found in deep caves in the Oregon desert. The oldest of the droppings have been carbon-dated to be approximately 14,340 years old. Willerslevs faeces samples clearly contain two main genetic types of Asian origin that are unique to present-day North American Indians. Not only is this proof that the American Indians are descendants of the first immigrants to the continent, it is also proof that immigration took place approximately 1,000 years earlier than otherwise believed.

The American continent was the last of the worlds continents to be populated. There are many contradictory and more or less well-founded scientific theories on when this occurred and from where the first immigrants came. These theories span from immigration via the icy Atlantic Ocean to Thor Heyerdahls papyrus boat expeditions from Africa to America. The most accepted theory is based on findings of stone tools from the Clovis culture in soil layers dating back to approximately 13,000 BC. According to the theory, people from Siberia migrated, perhaps in search of mammoth, across the land bridge that once connected Siberia and North America. From there, they continued south and spread out across the American continent. The migration passed through a corridor that opened up approximately 14,000 years ago in the giant glacier that covered the American continent. But these new findings call this immigration theory into question......... Posted by: Janet      Read more         Source

April 3, 2008, 8:42 PM CT

DNA analysis of California wolverine

Preliminary results from DNA analysis of wolverine scat samples collected on the Tahoe National Forest do not match those of historic California wolverine populations, as per U.S. Forest Service scientists.

Geneticists with the agencys Rocky Mountain Research Station recently began analyzing samples, when wildlife biologists with the Tahoe National Forest and California Department of Fish and Game began sending hair and scat samples they collected from wolverine detection sites on the national forest to a lab in Missoula, Mont.

The interagency effort began in March after an Oregon State University graduate student working on a cooperative project with the U.S. Forest Services Pacific Southwest Research Station photographed a wolverine, an animal whose presence has not been confirmed in California since the 1920s.

DNA analysis is critical to researchers working to determine if the animal first photographed on February 28 and in later detection work is a wolverine that dispersed from outside of California, escaped from captivity or is part of a historic remnant population.

Key findings from the preliminary analysis indicate the animal in the photographs is a male wolverine that is not a descendent of the last known Southern Sierra Nevada population, said Bill Zielinski, a Forest Service scientist with the Pacific Southwest Research Station and an expert at detecting wolverine, marten and fisher. It also does not genetically match populations in Washington, he said......... Posted by: Kelly      Read more         Source