Glow in the dark terrorists

A recent paper in Nature Chemical Biology (arm and leg subscription required) describes a engineered yeast strain engineered to sniff out TNT. First they had to clone many G protein signalling components into a yeast strain such that mammalian olfactory receptor signalling functioned. Then they screened a library of cDNAs from olfactory receptors to obtain a rat olfactory receptor that responds to TNT. This signaling pathway then initiated the expression of green fluorescent protein, thus the yeast glowed green when in the presence of trace amounts of TNT and an awesome biosensor is born. Great work from Dr. Danny Dhanasekaran at Temple University School of Medicine.

The smell of food can kill you

We have previously discussed the subject of caloric restriction and longevity to great lengths. However, in a surprising twist, it seems that just the smell of food can reverse the anti-aging benefits of dieting: "Smell is an ancient sensory system present in organisms from bacteria to humans. In the nematode Caeonorhabditis elegans, gustatory and olfactory neurons regulate aging and longevity. Using the fruit fly, Drosophila melanogaster, we showed that exposure to nutrient-derived odorants can modulate life span and partially reverse the longevity-extending effects of dietary restriction. Furthermore, mutation of odorant receptor Or83b resulted in severe olfactory defects, altered adult metabolism, enhanced stress resistance, and extended life span. Our findings indicate that olfaction affects adult physiology and aging in Drosophila, possibly through the perceived availability of nutritional resources, and that olfactory regulation of life span is evolutionarily conserved.^"