Auto-fluorescence of lignin in a root-hypocotyl cross-section of the nst1-1 nst3-1 double mutant shows a conspicuous absence of lignified secondary xylem. Wood is formed from secondary xylem tissue consisting of cells with a heavily thickened secondary cell wall that is enriched in lignin and cellulose. In contrast, primary cell walls are composed mainly of polysaccharides (including cellulose), but contain very little lignin. Wood formation occurs through a complex series of steps involving cell division and expansion and the biosynthesis of lignin and cellulose. In addition, heartwood (darker wood at the center of the trunk) forms in many tree species through a highly regulated process of programmed cell death.

Electron micrograph of the NIST "cell puller," which measures the mechanical properties of a living cell. After the cell spreads and adheres to the center of the 200-micrometer-wide circular platform, half of the platform is pulled slowly away, while a sensor connected to the other half measures the force on the cell. Credit: D. Serrell/NIST Researchers at the National Institute of Standards and Technology (NIST) have developed a microelectromechanical system (MEMS) cell-stretcher that can measure the mechanical properties of a living cell, such as its ability to stick to a surface. The new device is expected to enable novel studies of cell mechanics, which influence basic cell functions such as growth and division, and diseases such as sickle cell anemia and asthma.

One of the mysteries of the brain is how it avoids ending up in a state of chaos, something which happens only on exceptional occasions, when it can lead to epileptic fits. Scientists at Karolinska Institutet have now uncovered a new mechanism controlling how the brain keeps its neuronal activity in check.

As the national push for alternative energy sources heats up, researchers at the University of Rochester have for the first time identified how genes responsible for biomass breakdown are turned on in a microorganism that produces valuable ethanol from materials like grass and cornstalks.

While humans can survive large temperature fluctuations, such species as corals are only comfortable within a 12-degree temperature range. And rising global temperatures appear to be threatening their survival, according to Drew Harvell, Cornell professor of ecology and evolutionary biology.

Ecosystems are such intricate webs of connections that few studies have been able to explore exactly what happens when a species dies out.

A new genus of millipede was recently discovered by a Northern Arizona University doctoral student and a Bureau of Land Management researcher.