- Surprising Discovery: Multicellular Response Is 'All For One'
ScienceDaily (May 10, 2008)
Real or perceived threats can trigger the well-known "fight or flight response" in humans and other animals. Adrenaline flows, and the stressed individual's heart pumps faster, the muscles work harder, the brain sharpens and non-essential systems shut down. The whole organism responds in concert in order to survive.
At the molecular level, it has been widely assumed that, in single-celled organisms, each cell perceives its environment -- and responds to stress conditions -- individually, each on its own to protect itself. Likewise, it had been thought that cells in multicellular organisms respond the same way, but a new study by scientists at Northwestern University reports otherwise.
The Northwestern researchers demonstrated something very unexpected in their studies of the worm C. elegans: Authority is taken away from individual cells and given to two specialized neurons to sense temperature stress and organize an integrated molecular response for the entire organism.
The study, with results that show a possible parallel with the orchestrated "fight or flight response," will be published in the May 9 issue of the journal Science....
- Bread Mold May Unlock Secret To Eliminating Disease-causing Genes
ScienceDaily (May 11, 2008)
When most people discover mold on their bread, they immediately throw it out. Others see a world of possibilities in the tiny fungus. A University of Missouri scientist, along with a collaborative research team, has examined a new mechanism in the reproductive cycle of a certain species of mold. This mechanism protects the organism from genetic abnormalities by "silencing" unmatched genes during meiosis (sexual reproduction). The finding could have implications for higher organisms and may lead to precise "targeting" of unwanted genes, such as those from the HIV virus.
"Meiotic silencing also occurs in worms, mice and human beings," said Patrick Shiu, assistant professor of biological sciences in the MU College of Arts and Science. "It's unlikely that all share the same mechanism, but the principle of targeting unpaired DNA for silencing seems to be found in both simple and complex organisms. Knowing the process of how DNA in molds is targeted for silencing could be important for silencing genes you don't want to be expressed, like disease-causing genes."
Shiu and his colleagues discovered that each sexual cell in mold has an internal mechanism that "scans" paired chromosomes for anomalies. The researchers found that when one chromosome in a pair carries an extra copy of a gene not found in its partner chromosome, it is a good indication of an intruder and the fungus will "turn off" all copies of that gene during meiosis. The researchers call this process "meiotic silencing by unpaired DNA," or MSUD.....
- Magnet Lab Researchers Make Observing Cell Functions Easier
ScienceDaily (May 12, 2008)
Now that the genome (DNA) of humans and many other organisms have been sequenced, biologists are turning their attention to discovering how the many thousands of structural and control genes -- the "worker bees" of living cells that can turn genes on and off -- function.
To do that, they need to develop new techniques and tools. Scientists in the Optical Microscopy group at the National High Magnetic Field Laboratory at Florida State University, working in collaboration with researchers from the University of Alberta in Canada and the University of California, San Diego, have done just that, and in the process have produced back-to-back articles in the journal Nature Methods.
In the first paper, magnet-lab biologists Michael Davidson and Kristen Hazelwood worked with researchers from the University of Alberta to create two new fluorescent-protein biosensors, molecular "beacons" that can tell if there is activity within a cell. The biosensors can be used simultaneously to monitor two separate dynamic functions in a single cell -- a key to understanding how different proteins and enzymes (the biomolecules that cause chemical reactions) work together to complete the daily chores that help cells grow and divide. Knowing how cells work together can help researchers learn a great deal more about tumors and developmental biology, among many other things.
- Human Aging Gene Found In Flies
ScienceDaily (May 12, 2008)
Scientists funded by the Biotechnology and Biological Sciences Research Council (BBSRC) have found a fast and effective way to investigate important aspects of human aging. Working at the University of Oxford and The Open University, Dr Lynne Cox and Dr Robert Saunders have discovered a gene in fruit flies that means flies can now be used to study the effects aging has on DNA. In new work published today in the journal Aging Cell, the researchers demonstrate the value of this model in helping us to understand the aging process. This exciting study demonstrates that fruit flies can be used to study critical aspects of human aging at cellular, genetic and biochemical levels.
Dr Lynne Cox from the University of Oxford said: "We study a premature human aging disease called Werner syndrome to help us understand normal aging. The key to this disease is that changes in a single gene (called WRN) mean that patients age very quickly. Scientists have made great progress in working out what this gene does in the test tube, but until now we haven’t been able to investigate the gene to look at its effect on development and the whole body. By working on this gene in fruit flies, we can model human aging in a powerful experimental system."
Dr Robert Saunders from The Open University added: "This work shows for the first time that we can use the short-lived fruit fly to investigate the function of an important human aging gene. We have opened up the exciting possibility of using this model system to analyse the way that such genes work in a whole organism, not just in single cells.”
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