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April 15, 2009
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This 2-hour-old fly embryo already has a blueprint for its formation, and the process for following it is so precise that the difference of just a few key molecules can change the plans. Here, blue marks a high concentration of a key signaling protein that directs the formation of the fly’s head. It also regulates another important protein (green) that further maps the head and thorax structures and partitions the embryo in half (red is DNA). The yellow dots overlaying the embryo plot the concentration of the “blue” versus “green” proteins within each nucleus. Courtesy of Princeton University physicists William Bialek and Thomas Gregor.
This image was a finalist in 2008 Drosophila Image Award.
When scientists made the remarkable discovery that they could reprogram human skin cells to the embryonic state, their excitement was tempered by the use of viruses in the reprogramming process. Viruses insert their genetic material into the cells’ chromosomes, becoming permanent fixtures that could potentially cause cancer. Now, a team led by cell biologist James A. Thomson of the University of Wisconsin-Madison has found a way to reprogram skin cells using plasmids, which leave behind no genetic traces. The new method removes a major obstacle in the use of these stem cells in research and potential therapeutic applications.
NIH’s National Center for Research Resources also supported this work.
Banks have security guards, clubs have bouncers and our cells have proteins like P-gp that keep out certain molecules and potentially harmful chemicals. Unfortunately, P-gp also actively pumps out drugs designed to treat cancer, HIV and psychiatric diseases. As a result, the medicines don’t have a chance to work. Biophysicist Geoffrey Chang at The Scripps Research Institute led a research team that used X-ray crystallography to peer inside the structure of P-gp. What the scientists learned could lead to new drugs that can sneak past P-gp to get inside cells so they can treat cancer or other diseases.
Antibiotic resistance enables infections that were once easily cured to emerge with a vengeance. Chemist Vern Schramm of the Albert Einstein School of Medicine and colleagues at Industrial Research Ltd. have devised a powerful strategy to zap microbes, including the notorious E. coli 0157:H7 responsible for lethal food poisoning. The scientists made a molecule that locks onto a microbial enzyme, blocking the bacterium from “talking” to neighbors and spreading resistance. In lab tests, the molecule completely prevented infection even after many generations of growth with no resistance. Since other dangerous microbes use the same communication strategy, the approach may have broad applications.
What exactly is systems biology? How long has it been around? Why would someone consider a career in it? According to Ravi Iyengar, a biochemist at Mt. Sinai School of Medicine, systems biology is a holistic way of studying biology at any level—molecular, cellular, individual organism or groups of organisms. Researchers have studied these systems for a long time, but they are just beginning to understand the relationships between the different levels of organization. This more complete understanding allows scientists to figure out why a drug works, as well as to identify the molecular details needed to design new drugs.