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the Pulse of a Gene in Living Cells
When a gene is expressed or "turned on," genetic information is transferred from DNA into RNA. This process, known as transcription, is crucial for translating the gene's message into a functional protein. Diseases such as cancer can result when genes turn on at the improper time or in the wrong part of the body. Researchers customarily use microarrays (also known as "gene chips") to assess gene expression in tumors and other tissues. But with millions of cells involved, microarrays reflect only "average" gene expression. Just how a gene is transcribed in a single cell-continuously, intermittently or some other way-has largely been a mystery. Now, in observing a gene that plays a major role in how an organism develops, the Einstein researchers observed a phenomenon that until now has been indirectly observed and only in bacteria: pulses of transcription that turn on and off at irregular intervals. Dr. Singer and his co-workers used a fluorescent marker that sticks to the gene only when it is active. Under a microscope, this fluorescent marker appears when the gene turns on, then disappears (gene "off") and then appears again (gene "on")......... Posted by: Kelly Permalink Source More than drought affecting wheat yields
Dr. Tom Allen, Experiment Station assistant research scientist and plant disease diagnostician, saw more than 150 wheat samples sent to the Great Plains Diagnostic Network lab this growing season, in addition to 400-plus samples the plant pathology staff gathered across the Panhandle. Ninety-five percent of these samples were diagnosed with the wheat streak mosaic virus. In addition, 50 percent of the samples contained maize red stripe virus, more commonly known as High Plains virus. Both diseases are vectored by the wheat curl mite, Allen said. And so far, there's no treatment for either the viruses or the mite. The Great Plains Diagnostic Network is a part of a national plant disease monitoring system, which is divided into five regions. The Amarillo facility, a satellite lab to one at Kansas State University, is operated under the Experiment Station's plant pathology program, headed by Dr. Charlie Rush. Samples came by mail, through Texas Cooperative Extension agents or were dropped off by producers, Allen said. They came from as far north as Nebraska and as far south as Dallas and the Hill Country, Rush said, making this one of the most widespread years for wheat streak mosaic damage......... Posted by: Erica Permalink Source Evolution Of Hot Springs Microorganisms
These hot springs in Nevada, known as the Three Buddhas, harbor microorganisms known as archaea that thrive where no other life can. UGA researcher Chuanlun Zhang and his colleagues have proposed a new hypothesis on the origin of relatives of these hot springs microorganisms that live in low-temperature environments.
Credit: University of Georgia In the 1990s, however, researchers discovered that archaea occur widely in more mundane, low-temperature environments such as oceans and lakes. Now, scientists from the University of Georgia and Harvard University find evidence that these low-temperature archaea might have evolved from a moderate-temperature environment rather than from their high-temperature counterparts - as most researchers had believed. The results appear in the June 2006 issue of the journal Applied and Environmental Microbiology. "Archaea represent one of the three domains of life on Earth," said Chuanlun Zhang, lead author of the study and associate professor of marine sciences at UGA. "Understanding their evolution may shed light on how all life forms evolve and interact with the environment through geological history." Zhang and colleagues examined a common group of archaea known as Crenarchaeota. He explains that the Crenarchaeota's low-temperature success may involve a unique molecule known as crenarchaeol that allows the organism's cell membrane to remain flexible in cooler environments......... Posted by: Erica Permalink Source Plant Diseases Threaten Chocolate Production
"Plant diseases are the most important constraints to cacao production and the continued viability of the world's confectionary trades," said Randy Ploetz, plant pathology professor at the University of Florida, Homestead, FL. Currently, 4 million metric tons of beans worth more than $4 billion are produced each year. The global chocolate market is worth $75 billion annually. According to Ploetz, the three most important and damaging cacao diseases are black pod, frosty pod, and witches' broom. Black pod occurs worldwide and has the largest impact, while frosty pod and witches' broom are restricted to tropical America. "Frosty pod and witches' broom would devastate cacao production in West Africa, where almost 70 percent of all production occurs," said Ploetz. "In this region, either disease could reduce yields by an additional one million more metric tons per year," he said. New insights and current research on cacao diseases, as well as resistance to and management of the diseases, will be addressed during the Cacao Diseases: Important Threats to Chocolate Production Worldwide symposium held July 30 from 1:30-5 p.m., during the joint annual meeting of The American Phytopathological Society, Canadian Phytopathological Society, and the Mycological Society of America. The joint meeting will be held July 29-August 2, 2006, at the Centre des Congrès de Quebec, Quebec City, Quebec, Canada......... Posted by: Erica Permalink Source Sugar Maples In Jeopardy
The forest that originally covered Mount Royal consisted of sugar maples, hickories, and red oaks. As per Brisson and master's student Joëlle Midy, sugar maples still predominate today, but Norway maples will take over in the future. In a presentation to ACFAS on May 17, Brisson noted that a census of trees more than 10 years old found 4,200 sugar maples and 1,200 Norway maples, but the ratio was reversed in younger trees, with three times more Norway maples than sugar maples. Fast-growing and pollution-resistant, Norway maples line the streets of Montreal. Their invasion of Mount Royal is due to a short-sighted effort to reforest parts of the park in the 1960s and '70s. The original maple trees on the upper campus are well preserved, but small Norway maples now dominate the area between the metro station and the residences. The Norway maple closely resembles the sugar maple - in fact, it's hard to tell them apart until the leaves begin to turn. Sugar maples turn red and orange, while Norway maples turn yellow and ochre. That explains why the streets of Montreal put on a much less flamboyant show in the fall than the forests of the Laurentians or the Eastern Townships......... Posted by: Erica Permalink Source Algae's Protein Ttails" Create Motion
In the early online edition of the Proceedings of the National Academy of Sciences, scientists from the University of Arizona and Brown University explain how flagella allow these algae to get the energy they need to multiply and create colonies - the critical secret that allowed them to evolve into multicellular organisms. This is the first evidence that flagella not only help organisms move, but can help them feed at a rate that allowed them to evolve to a larger size," said Thomas Powers, an assistant professor of engineering at Brown who studies microorganisms in motion. "This is a critical piece of information, since understanding how one-celled life forms evolve into a number of-celled ones is a fundamental question in biology". The team studied a group of green algae known as the volvocines, organisms so common they can be found in puddles of rain. Biologists study the group, which runs the gamut from single-celled organisms to teeming colonies, to understand how cells differentiate and multiply. But how did the volvocines jump from solo cells to Volvox, a colony of as a number of as 50,000 cells?........ Posted by: Erica Permalink Source What Lies Beneath
A group of very old tubeworms (Lamellibrachia luymesi and Seepiophila jonesi) living on the same piece of carbonate rock as large colonies of the gorgonian Callogorgia Americana americana, with brittle stars and a galatheid crab crawling on the gorgonians. Credit: Derk Bergquist
Scientists Harry Roberts and Bob Carney are combing the most unique continental slope in the world to study some of the most unique animal communities on the planet - all just off the coast of Louisiana. Roberts and Carney are studying 14 different sites where oil and gas seep up from the bottom of the Gulf. In particular, they are studying the animals that live near these "seeps." These organisms include bacteria that feed on hydrogen sulfide gas, a by-product of the oil and gas seepage; tube worms, mussels and clams that serve as hosts to those bacteria; and shrimp, crabs, fish, snails and starfish that, in turn, feed on the worms, mussels and clams. These animal communities are unique because they only exist near these seeps, and because the bacteria at the base of the food chain are "chemosynthetic," or grow without sunlight. The large number of oil and gas seeps and the vast amount of salt under the Gulf floor near Louisiana's coast, along with all the sediment dumped into the Gulf by the Mississippi River, make the continental slope off the coast of Louisiana unique. "It's the most complicated continental slope in the world, geologically," Roberts said. "There are more seep communities off the coast of Louisiana than most places in the world. The salt, the oil and gas and the sediment create a very dynamic geologic framework"......... Posted by: Kelly Permalink Source Cassava Plants To Fight Hunger In Africa
The findings could help ease hunger in a number of countries where people rely heavily on the cassava plant (Manihot esculenta) as a primary food source, said Richard Sayre, the study's lead author and a professor of plant cellular and molecular biology at Ohio State University. The scientists used a gene from the bacterium E. coli to genetically modify cassava plants. The plants, which were grown in a greenhouse, produced roots that were an average of 2.6 times larger than those produced by regular cassava plants. "Not only did these plants produce larger roots, but the whole plant was bigger and had more leaves," Sayre said. Both the roots and leaves of the cassava plant are edible. Cassava is the primary food source for more than 250 million Africans - about 40 percent of the continent's population. And the plant's starchy tuberous root is a substantial portion of the diet of nearly 600 million people worldwide. Sayre said he hopes to offer these plants to countries where cassava is an important crop. The current study appears in the online early issue of the Plant Biotechnology Journal. Sayre collaborated with Ohio State colleague Uzoma Ihemere and researchers from BASF Plant Science in Research Triangle Park, N.C., and BARC-West in Beltsville, Md., who formerly worked on this project in his laboratory......... Posted by: Erica Permalink Source Trees Suffer From Diseases In Rain-soaked Midwest
Diseases affecting tree leaves are being found in sycamore, ash, crabapple and oak trees. Eventhough these foliar diseases are often not the most life-threatening of plant diseases, they frustrate homeowners, said Janna Beckerman, a plant pathologist in Purdue University's Department of Botany and Plant Pathology. "Otherwise healthy trees can tolerate several seasons of partial defoliation without suffering significant injury," Beckerman said. "In fact, trees produce such an abundance of leaves that some loss of foliage is not a major cause for concern." She also said, however, that homeowners will be able to notice as little as 5 percent defoliation, and as little as 10 percent defoliation may cause homeowners to panic. While small amounts of leaf loss may begin to be noticed, Beckerman said that homeowners can't be certain their tree is suffering from disease until about one-third defoliation occurs. Some examples of the more prominent diseases showing up in Indiana include sycamore, ash and oak anthracnose; apple scab; cedar-apple rust; plum pockets; and peach leaf curl. Symptoms of the various forms of anthracnose consist of brown leaves, brown spots on leaves that spread down the mid-vein, or a loss of leaves......... Posted by: Erica Permalink Source Mystery Of Flowering Plants
Claude dePamphilis, associate professor of biology at Penn State, is the principal investigator of the Floral Genome Project and the senior author of the paper. "We found a concentration of duplicated genes that suggests a whole-genome duplication event in the earliest flowering plants," he says. "A polyploidy event early in the history of flowering plants could explain their sudden evolution." The results appear in a recent issue of Genome Research. One unexpected observation from the study is the relatively slow accumulation of mutations in primitive flowering plants like the yellow water lily (Nuphar). "We can view these basal angiosperms like the Hubble Space Telescope, which helps us get a deeper look into the early history of the universe--these plants allow us to take a deeper look into genomic history"......... Posted by: Erica Permalink Source |
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