Metabolic imbalances accompany the aging process in many organisms, and signaling mechanisms that allay or prevent these imbalances can extend lifespan. Two recent studies by Auwerx and colleagues, including one in this issue, identify a conserved signaling network centered on mitochondrial stress responses that promotes longevity in response to changes in mitochondrial translation and NAD(+) m...

A balanced supply of deoxyribonucleoside triphosphates (dNTPs) is one of the key prerequisites for faithful genome duplication. Both the overall concentration and the balance among the individual dNTPs (dATP, dTTP, dGTP, and dCTP) are tightly regulated, primarily by the enzyme ribonucleotide reductase (RNR). We asked whether dNTP pool imbalances interfere with cell cycle progression and are det...

Various electrolytes in test solutions applied to the skin were evaluated with regard to their effects on enhanced skin permeation of calcein as a model permeant by electroporation (EP), which is a physical means to increase skin penetration by applying a high voltage pulse on the skin surface. Calcein solution (1.0 mM) containing different electrolytes at a concentration of 150 mM was applied ...

BACKGROUND Models for predicting uptake and transport of chemicals in plants are applied in pesticide design, risk assessment, and environmental biotechnology. OBJECTIVE This review considers the theoretical basics of the most popular models, and discusses what they have in common. The line is drawn between models for neutral compounds, and models for weak and strong electrolytes. MAIN FEAT...