Mustard's spiciness linked to its hardiness
A small family of genes regulates not only the spiciness of mustard plants but also their prospects for survival, scientists report. What seems like a very slight difference in the genes alters the spice-building pathway in a wild mustard plant, according to the report, which appears in the journal Science.
This produces different enzymes in different plants that keep away specific insects. "We can predict when a plant has one form of the gene or the other, what kind of spice it has," said an author of the study, Thomas Mitchell-Olds, a biologist at Duke. The researchers placed 4,000 mustard plants of two different species in two meadows, on a mountaintop in Montana and in a valley in Colorado, and observed them for several years.
"We looked at what their death rate was, what percentage of leaves were eaten and how many kids different genotypes had," Mitchell-Olds said.
When plants with the version of the enzyme normally found in Colorado were planted in Montana, they were attacked by insects and struggled to survive. The same thing happened when Montana plants were planted in Colorado. "In Colorado there was lots of damage," Mitchell-Olds said. "It could have been because there were lots of insects and because it was warmer."
The tale of these two species is just one story out of many, he said, adding, "Presumably other species might have equally interesting stories we don't know about."
Taking the measure of a single molecule
For the first time, a device can measure the mass of a single molecule. Traditionally in mass spectrometry, tens of millions of particles are weighed to calculate the mass of a single molecule.
But researchers from the United States and France have developed a device that can measure just one; they describe it in the journal Nature Nanotechnology as a vibrating, bridge-like structure that is only a couple of millionths of a meter in length.
"One way to imagine it is like a violin string," said Michael Roukes, a physicist at the California Institute of Technology and one of the study's authors. "If you pluck a violin string it will vibrate at some frequency - so when a particle arrives on the resonator the frequency changes, and we're measuring that change." By measuring the change, the researchers are able to calculate a molecule's mass, Roukes said.
The instrument took the scientists 12 years to develop. A previous iteration of the technology did not account for where on the resonator a molecule landed, which, as with a violin, affects the shifts in frequency. To correctly determine a molecule's mass, the researchers had to analyse measurements of about 500 identical particles.
But the new technique allows them to take multiple measurements simultaneously and back calculate a molecule's mass based on a single particle.
Sindya N Bhanoo
New York Times News Service
A small family of genes regulates not only the spiciness of mustard plants but also their prospects for survival, scientists report. What seems like a very slight difference in the genes alters the spice-building pathway in a wild mustard plant, according to the report, which appears in the journal Science.
This produces different enzymes in different plants that keep away specific insects. "We can predict when a plant has one form of the gene or the other, what kind of spice it has," said an author of the study, Thomas Mitchell-Olds, a biologist at Duke. The researchers placed 4,000 mustard plants of two different species in two meadows, on a mountaintop in Montana and in a valley in Colorado, and observed them for several years.
"We looked at what their death rate was, what percentage of leaves were eaten and how many kids different genotypes had," Mitchell-Olds said.
When plants with the version of the enzyme normally found in Colorado were planted in Montana, they were attacked by insects and struggled to survive. The same thing happened when Montana plants were planted in Colorado. "In Colorado there was lots of damage," Mitchell-Olds said. "It could have been because there were lots of insects and because it was warmer."
The tale of these two species is just one story out of many, he said, adding, "Presumably other species might have equally interesting stories we don't know about."
Taking the measure of a single molecule
For the first time, a device can measure the mass of a single molecule. Traditionally in mass spectrometry, tens of millions of particles are weighed to calculate the mass of a single molecule.
But researchers from the United States and France have developed a device that can measure just one; they describe it in the journal Nature Nanotechnology as a vibrating, bridge-like structure that is only a couple of millionths of a meter in length.
"One way to imagine it is like a violin string," said Michael Roukes, a physicist at the California Institute of Technology and one of the study's authors. "If you pluck a violin string it will vibrate at some frequency - so when a particle arrives on the resonator the frequency changes, and we're measuring that change." By measuring the change, the researchers are able to calculate a molecule's mass, Roukes said.
The instrument took the scientists 12 years to develop. A previous iteration of the technology did not account for where on the resonator a molecule landed, which, as with a violin, affects the shifts in frequency. To correctly determine a molecule's mass, the researchers had to analyse measurements of about 500 identical particles.
But the new technique allows them to take multiple measurements simultaneously and back calculate a molecule's mass based on a single particle.
Sindya N Bhanoo
New York Times News Service