Scientific discoveries this week: 2/25/13

Johns Hopkins
Researchers at Johns Hopkins University found that a protein known for turning on genes to help them survive low oxygen conditions also slows down the copying of DNA strands. This effectively shuts down the growth of new cells. Their discovery has wide-ranging implication due to DNA replication and new cell growth being key factors in diseases such as cancer. The protein HIF-1α can switch hundreds of genes on or off in response to low oxygen conditions. HIF-1α can also stop new cells from forming. The researchers looked at how the protein affects DNA replication by comparing cells in low-oxygen conditions to cells kept under normal conditions. The cells in the low oxygen conditions stopped dividing, but had as much DNA replication systems as the normal cells. The difference was that the nondividing cells were being affected by HIF-1α which was binding to a protein and preventing the replication process from occurring.

University of Pennsylvania
The reprogramming of alpha cells into beta cells could offer a novel approach for treating type 2 diabetes. Researchers at University of Pennsylvania found a way to modify cell nuclear material called chromatin to induce the expression of beta cell genes in alpha cells. This method could lead to a way to treat diabetics by reactivating their insulin-producing beta cells. According to lead author Klaus H. Kastner, “This would be a win-win situation for diabetics they would have more insulin-producing beta cells and there would be fewer glucagon-producing alpha cells.” Type 2 and type 1 diabetics both lack insulin production, but type 2 diabetics also produces too much glucagon. Alpha cells are responsible for synthesizing and secreting glucagon, which elevates glucose levels in the blood. The team discovered that many genes in alpha cells are marked by histone modifications. This included many genes important in beta-cell function. They found that in one state, when a certain gene is turned off, the gene can be activated by removing a modification that represses the histone. They then determined that they might use this method to reprogram alpha cells towards the beta cell phenotype to produce the necessary cells.

Emory University
Biologists at Emory University found that when fruit flies sense parasitic wasps in their environment, they lay their eggs in an alcohol-soaked environment, essentially forcing their larvae to consume alcohol as a drug to combat the wasps. The adult flies anticipate an infection risk and thus lay their eggs in alcohol. This discovery adds to the evidence that using toxins in the environment to medicate offspring may be common across the animal kingdom. The biologists also determined that adult fruit flies detect wasps by sight and have better vision than was previously thought. The larvae, Drosophila melanogaster, eats the rot, or fungi and bacteria, that grows on overripe, fermenting fruit. The larvae have evolved resistance to toxic alcohol levels which can range to 15 percent. Small endoparasitoid wasps are major killers of fruit flies as they inject their eggs inside the larvae along with venom that suppresses their hosts’ cellular immune response. If the fly fails to kill the wasp egg, a wasp larvae hatches inside the fruit fly larvae and eats its host. The alcohol improves the survival rate of fruit flies due to their high tolerance of the toxic effects of alcohol compared to the wasps’ low tolerance.



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