Microbiology

Physical alterations of DNA in chromosomes can cause serious diseases such as Down syndrome, Prader-Willi syndrome, or cancer. Likewise, changes to the physiological environment of cells—with drugs or toxins, for example—can alter their metabolic output. To track these processes, scientists need ways to mark genes and their protein products. The first method (http://www.cshprotocols.org/cgi/content/full/2007/10/pdb.prot4743) describes how to grow cells from bacteria, yeast, insects, or mammals in media containing the stable isotope nitrogen-15. As the cells grow, they produce nascent…

Copper is an essential part of our lives. From copper pipes and wires - to important copper-containing proteins in the body, copper is necessary for healthy growth and neurological development. Researchers at the Montreal Neurological Institute at McGill University are studying how copper is processed in our bodies and its distinct role in early development. Their findings, published in a recent edition of the journal Cell Metabolism, identify a new role for two proteins involved with copper regulation. This study may lead to a better understanding of how to treat individuals affected by…

Recent data from the Lung Allograft Rejection Gene expression Observational (LARGO) study provides compelling evidence that profiling gene expression in peripheral blood can detect organ rejection in lung transplant patients. Data from the study shows that the immune responses of lung transplant recipients can result in novel molecular signatures identifying the absence or presence of acute cellular rejection (ACR). That molecular signature can be identified using the quantitative real-time polymerase chain reaction (RT-PCR), a technology that measures the intracellular RNA levels of…

New studies in the laboratory of Dr. Darwin J. Prockop, Director of Tulane University’s Center for Gene Therapy, are shedding light on the previously mysterious mechanism through which even relatively small amounts of stem/progenitor cells taken from a patient’s own bone marrow enhance repair of damaged tissues. The cells not only differentiate to replace injured cells, as had been understood, but they also stimulate the proliferation and differentiation of stem cells already present in the injured tissue and they transfer mitochondrial DNA to local cells in which the mitochondria (the…

Scientists have determined that a specific class of PCB causes significant developmental abnormalities in rat pups whose mothers were exposed to the toxicant in their food during pregnancy and during the early weeks when the pups were nursing. Polychlorinated biphenyls (PCBs), used mostly as coolants and lubricants beginning in the 1930s, were banned in 1977. Early toxicology studies focused mostly on a subset of PCBs known as coplanar PCBs, which were shown in cell culture and animal models to pose a serious health risk. Recent studies, however, have shown that non-coplanar PCBs are…

Despite the fact that they both infect the liver, the hepatitis A and hepatitis C viruses actually have very little in common. The two are far apart genetically, are transmitted differently, and produce very different diseases. Hepatitis A spreads through the consumption of fecal particles from an infected person (in pollution-contaminated food or water, for example), but hepatitis C is generally transmitted only by direct contact with infected blood. Hepatitis A produces fever, nausea and abdominal pain that can last for weeks, but rarely lead to death; hepatitis C, by contrast, often…

Working with fruit flies, scientists at Johns Hopkins have discovered a protein required for two neighboring cells to fuse and become one "super cell." Most cells enjoy their singular existence, but the strength and flexibility of muscles relies on hundreds or even thousands of super cells that make large-scale motion smooth and coordinated, such as flexion of a bicep. The newly discovered protein, dubbed Solitary, coordinates the movement of tiny molecular delivery trucks to a cell's surface. Cells that lack Solitary stay, well, solitary. "They refuse to fuse," says Hopkins assistant…

The aphid Acyrthosiphon pisum depends on a bacterial symbiont, Buchnera aphidicola, for amino acids it can't get from plants. The aphid, in turn, provides the bacterium with energy and carbon as well as shelter inside specialized cells. Such interdependent relationships are not unusual in the natural world. What is unusual, report Helen Dunbar, Nancy Moran, and colleagues in a new study published this week in the open access journal PLoS Biology, is that a single point mutation in Buchnera's genome can have consequences for its aphid partner that are sometimes detrimental, and sometimes…

Proteins, which form much of the molecular machinery required for life, are the targets of most drug molecules. One third of all proteins are membrane proteins – embedded within the cell’s fatty outer layer. While scientists can easily study the other two-thirds using such tools as antibodies, they have not had such methods to investigate the membrane-embedded portions of proteins. To probe the secrets of these seemingly inaccessible proteins, researchers at the University of Pennsylvania School of Medicine have designed peptides that are able to bind to specific regions of transmembrane…

Given the huge shortage of donor organs, researchers have been trying to find ways to transplant animal organs across different species (known as "xenotransplantation"), with the eventual aim of transplanting animal organs into humans. The major stumbling block, says Dr Muhammad Mohiuddin (US National Heart, Lung, and Blood Institute) in a paper in PLoS Medicine, is that the immune system in the animal receiving the organ tends to reject the transplant. Nevertheless, the recent development of genetically modified pigs that are more compatible with humans, "has reinstated hope for the success…