A cell responds to pollutants – such as dioxin – via intricate and complex biochemical pathways beginning with the interaction of the pollutant molecule with a cell surface receptor. Christopher Bradfield and colleagues used yeast as a model system to elucidate the steps involved in the pathway that regulates vertebrate cell response to dioxin, the aryl hydrocarbon receptor (AHR) signal transduction pathway. To assess the molecules and pathways involved in the AHR pathway, the research group studied

Wolbachia have a thing against males. A member of one of the most diverse groups of bacteria, called Proteobacteria, this parasitic “endosymbiont” lives inside the reproductive cells of a wide variety of the nearly one million species of arthropods, including insects, spiders, and crustaceans.

Wolbachia’s effects range from beneficial to pathological, but if the host is male, the infection often turns out badly. The reason is the Wolbachia are transmitted through females, and to increase th

Essential for normal central nervous system function, dopamine signaling mediates physiological functions as diverse as movement and lactation. The dopamine transporter (DAT) is involved in terminating dopamine signaling by removing the dopamine chemical messenger molecules from nerve synapses and returning them into the releasing neurons (a process called reuptake). DAT can also bind amphetamine, cocaine, and other psychostimulants, which inhibit dopamine reuptake, and, in the case of amphetamine, a

Voles are pedestrians, too, and need just as much help crossing the road as the big animals, says new research from the University of Alberta.

“There has been a mindset that bigger is better–driven by research on large mammals and especially bears,” said Dr. Colleen Cassady St. Clair, from the Department of Biological Sciences. “This research shows that small affordable culverts, which can be placed with high frequencies while building roads, are very effective conduits for small mammals.

While it might not seem so the next time you go searching for your car keys, scientists at the University of Pennsylvania have shown that memories are not as fluid as current research suggests. Their findings challenge the prevailing notion on how memories are stored and remembered – or that a recalled memory could be altered or lost as it is “re-remembered.”

“Current theories of memory state that the act of remembering turns a stored memory into something malleable that then needs to be re

Scientists have known for some time that some social insects undergo dramatic behavioral changes as they mature, and now a research team has found that the brains of a wasp species correspondingly enlarge as the creatures engage in more complex tasks.

“The amount of change is striking,” said Sean O’Donnell, a University of Washington associate professor of psychology and lead author of a new study published in the February issue of Neuroscience Letters. “It is easily apparent with magni

New model may help researchers understand and treat human digestive problems

Every animal — including humans — is home to “friendly” gut bacteria that help digest food and perform other important functions. Now, a tiny, transparent fish is literally offering biologists a new window into these mutually beneficial symbiotic relationships.
Researchers at Washington University School of Medicine in St Louis have shown for the first time that zebrafish can be raised in a germ-free env

Blood cell formation depends on gene previously linked to leukemia

Researchers at Dana-Farber Cancer Institute have pinpointed a crucial gene on which the normal development of the body’s entire blood system depends. If the gene is absent, even the most basic blood stem cells cannot be generated. In a mutated form, this gene can cause a rare and devastating form of leukemia.

Called MLL, the gene makes a protein that regulates the activity of a number of other genes invol

A group of scientists at The Scripps Research Institute has proposed a new theory about the cause of Alzheimer’s disease, the progressive neurodegenerative disorder that currently afflicts some 4.5 million Americans.

According to the hypothesis, the disease arises as a consequence of inflammation, which creates abnormal metabolites out of normal brain molecules.

These abnormal metabolites then modify “amyloid beta” proteins in the brain and cause them to misfold. Misfolded amyloid

The esophagus isn’t merely a tube for food traveling from the mouth to the stomach, it also provides an environment for bacteria to live, according to a new study by NYU School of Medicine scientists that overturns the general belief that the esophagus is free of bacteria.

“People thought that the esophagus wasn’t hospitable to bacteria,” says Martin J. Blaser, M.D., Frederick King Professor and Chairman of the Department of Medicine, and Professor of Microbiology, an author of th

A strong antigen-specific T-cell response to HIV infection is important for controlling virus replication; however, because HIV selectively infects and replicates in CD4 T cells, increased number of these cells in response to viral infection may also be detrimental as these cells provide fuel for the infection to grow.

In the March 15 issue of the Journal of Clinical Investigation, Mark Feinberg and colleagues, of Emory University Vaccine Center, analyze the specific parameters of T-cell ac

Johns Hopkins Kimmel Cancer Center scientists have identified a switched-off family of genes that may prove to be a significant and early dent in a colon cell’s anti-cancer armor. The inactivated genes, called SFRPs – for secreted frizzled-related protein – put the brake on a pathway of cell-growth genes that is an early step en route to cancer. Because the way SFRP genes are altered-through the attachment of so-called methyl groups-is reversible, the findings, reported in the March 14 advance o

Scientists at the Carnegie Institution in Baltimore, MD, have found that certain cells involved in egg development in the fruitfly can be stimulated to revert to fully functioning stem cells. “This finding could lead to new sources of stem cells from other tissues and other animals,” commented Dr. Allan Spradling, director of the Carnegie department and co-author of the study published in the March 14 online issue of Nature.

The research conducted by Spradling — a Howard Hughes Medica

A new experiment by chemists from Stanford University and the University of Edinburgh has finally proven what beer lovers have long suspected: When beer is poured into a glass, the bubbles sometimes go down instead of up.

“Bubbles are lighter than beer, so they’re supposed to rise upward,” said Richard N. Zare, the Marguerite Blake Wilbur Professor in Natural Sciences at Stanford. ’’But countless drinkers have claimed that the bubbles actually go down the side of the glass. C

The mouse immune system develops antibodies capable of single-handedly neutralizing the SARS virus, researchers at the National Institute of Allergy and Infectious Diseases (NIAID) report in the April 1 issue of the Journal of Virology, available online March 12. NIAID is part of the National Institutes of Health (NIH).

This discovery affirms that researchers developing vaccines that trigger antibodies to the SARS virus are heading in the right direction. Vaccines can stimulate the immune s

Penn researchers successfully transplant cells that lead to new hair follicles

Researchers at the University of Pennsylvania School of Medicine have isolated stem cells responsible for hair follicle growth. The findings, published in the April issue of Nature Biotechnology, may serve as the foundation for new hair loss and skin grafting treatments.

Hair grows from cells located at the base of the hair follicle. Hair follicles continuously cycle through growth, rest, and re-gr