The common fruit fly circling your week-old peach has helped scientists zero in on a protein critical to the insect's eggshell formation.
The paradoxical finding gives scientists a better understanding of how the innermost protective eggshell layer forms as it points to a likely target for pesticide development, says Dr. Ellen LeMosy, developmental biologist in the Medical College of Georgia Schools of Medicine and Graduate Studies.
Her research team named the newly discovered protein palisade because knocking out the gene disrupted formation of a picket-fence-like line up of protein balls called vitelline bodies. Within 18 to 24 hours, the bodies should meld into a solid, transparent membrane that is the egg's first line of defense.
"You can take the outer layer of the eggshell off. With bleach, it dissolves and it just leaves this inner vitelline membrane and that is sufficient to maintain the structure," she says. "If the egg does not have external support, it would pop like a balloon. It's very soft." The membrane also helps keep the egg from drying out.
Without palisade, a key protein of the shell's membrane also gets taken up in the egg. "Think of the vitelline membrane as made up of four colors of brick and one of the colors falls into the oocyte. We don't know if there is any direct consequence of having that brick taken up by the oocyte: it could be just trash. But not having it in the eggshell means the vitelline membrane won't form properly, so the egg won't survive anyway," Dr. LeMosy says.
Palisade could prove a great target for pesticides, which today are largely neurotoxins, because humans don't have it, says Dr. LeMosy, corresponding author on the study published online in Developmental Biology. She notes that "good" insects, such as ladybugs and praying mantis that have a big appetite for other insects, could be potential casualties.
Her studies, which include the form and function of f
|Contact: Toni Baker|
Medical College of Georgia