The crystalline structures in the silk are so small that Yarger says it is impossible to look at the molecular makeup of the silk with conventional X-rays. "But the synchrotron analysis at the APS allows us to do this," Yarger said.
They found that at the molecular level, caddisfly silk differs greatly from other terrestrial spun silks such as those from spiders or silkworms. Caddisfly silk is phosphoratelated, meaning that after the amino acid chain that makes up the silk is created, phosphate molecules bond to the chain. Phosphates can act as bonding agents and are used to make some water resistant paints.
"The next step is to see how we might be able to mimic nature with this new motif we discovered," Yarger says.
Putting grasshoppers on a diet
Grasshoppers eat up crops, but farmers may soon have a chemical-free way to protect their plants from these voracious pests by turning their natural growth cycle against them.
Scott Kirkton, associate professor of biology at Union College observed that just before molting, a growth process in which an insect sheds its skin in order to mature to its next life stage, a grasshoppers insides become essentially too large for its outer shell. This compresses the grasshopper's tracheal system and makes it difficult for it to breathe. As a result, the team saw a reduction in the number of jumps per minute for the grasshoppers about to molt versus those that were not, suggesting that a compressed respiratory system causes a reduction in mobility.
From this, Kirkton hypothesizes that a lack of oxygen delivery to the grasshopper's body is a trigger for molting. Storing grains or crops at low oxygen levels would limit the oxygen the insects get and trigger molting. The resulting stunted growth cycle would create petite pests with petite appetites, leaving more crops to make their way to supermarket shelves.
|Contact: Tona Kunz|
DOE/Argonne National Laboratory