Volume 3 Issue 10, October 2007

Animals time events on scales that span from microseconds to days. In contrast to the technologies devised by humans to keep track of time, biology has developed vastly different mechanisms for timing across these different scales.

Live samples are intrinsically highly dynamic, yet techniques to monitor these complex environments usually reflect snapshots, thus making time-lapse imaging necessary to explore temporal progression of biological functions. Recent results indicate that exploiting some basic features of fluorescent protein maturation, such as green-to-red maturation of engineered proteins, should allow probing of temporally regulated information.

A continual commitment to exploring new scientific territory has led Pamela Silver on an oscillating path from physics and engineering to molecular biology and now to the development of engineering principles in the creation of cellular metrics.

The use of biocatalysts for glycoside bond formation is an attractive strategy in chemical synthesis, but the tight specificity of enzymes can be a significant limitation. An ingenious screening strategy has led to the discovery of a particularly plastic glycosyltransferase.

A fully synthetic three-component vaccine has been shown to induce high titers of antibodies against the mucin Tn antigen of human cancer cells. The vaccine's superior properties are a result of the covalent incorporation of a ligand for Toll-like receptors and the presentation of the vaccine in a liposome format.

Monitoring nutritional sufficiency is essential in optimizing bacterial survival strategies. Recent studies find that nutrient sensing is delocalized over many cell components. Adding to the complexity, some metabolite pools and cellular components contribute to more than one signal transduction pathway and to housekeeping functions.

Transmembrane electrochemical ion gradients are the thermodynamic forces exploited by living cells to drive specific substances across the membrane. A new study begins to reveal the molecular mechanisms by which a transporter protein harnesses these driving forces.

Cells and organisms have developed specialized systems to observe and respond to variables within their local environments. In this issue, we feature a collection of articles that focus on how biological systems measure space and time.