Life Sciences and Chemistry

At the heart of every cell, vital information is “written” on the DNA, a long molecular ribbon almost one meter long bundled inside the nucleus of the cell. For the DNA to fit inside this small space, it is rolled up like a ball of yarn in a highly organized structure called chromatin. Beyond its purely structural role, the spatial organization of DNA is essential to the basic processes of a cell’s life because it provides information that is added to that contributed by the genetic code. This ball-

Laboratory rats that have been repeatedly depleted of salt become sensitized to amphetamine, exhibiting an exaggerated hyperactive response to the drug and an unusual pattern of neuronal growth in a part of their brains, neuroscientists have found.

The researchers, headed by University of Washington psychologist Ilene Bernstein, discovered that nerve cells in the nucleus accumbens of sensitized rats have more branches and were 30 percent to 35 percent longer than normal. The nucleus accumbe

Heart ’patches’ and functioning kidney units cloned in cows

Advanced Cell Technology, Inc. (ACT) reported today that nuclear transplantation can be used to generate functional immune-compatible tissues. The research, which will appear in the July issue (cover story) of Nature Biotechnology, by ACT and its collaborators, provides the first experimental evidence that it may be possible to use cloning to generate medically important tissues and eliminate tissue rejection. Heart

Brown scientists have described a previously unknown but critical blood-clotting role for Arp2/3, a complex of seven proteins found in animal and plant cells.

Reporting in the June 15 issue of Blood, the scientists show that Arp2/3 complex is a cellular machine that drives a human blood platelet to change shape into a larger, more flattened form and begin the process of clotting. The link between what happens at the surface of a platelet and the mechanism of shape change within it has mystif

Pulses of laser light can make molecules react in ways that are impossible using classical test-tube chemistry. Molecules vibrate, and each molecule has its own “tone,” its own “melody.” It’s a question of finding the right key, and that is something that a “smart” laser beam can do. It can find its way to the right tone. In a new issue of the prestigious journal Nature it is shown how such a laser can be used to control photosynthesis molecules that gather light. This is the first time this fea

A tiny methane-producing microbe has revealed the existence of a new amino acid, researchers report. Two studies published in the current issue of the journal Science describe pyrrolysine, a nonstandard amino acid encoded in the RNA of bacteria-like members of the group Archaea. The findings suggest that the genetic code may be more adaptable than previously believed.

When scientists first began to unravel the genetic code more than four decades ago, they determined that the four DNA bases