SPIDER SILK

(SFX: ITSY BITSY SPIDER SONG)

     MOST PEOPLE THINK OF SPIDERS AS CREEPY CRAWLY THINGS THAT DON'T DO
MUCH EXCEPT WEAVE WEBS THAT GET IN YOUR WAY.  EVEN THE WEBS CAN BE CREEPY,
SINCE ONCE THEY GET TANGLED UP IN YOUR HANDS OR HAIR THEY'RE HARD TO GET OUT. 
BUT ITS JUST THAT TOUGHNESS, AS THE WEBS TWIST AND STRETCH THAT MAKES A
SPIDER'S WEB SO INTERESTING.  INCH PER INCH, SPIDER'S SILK IS ONE OF THE
STRONGEST MATERIALS AROUND.  IT'S FIVE TIMES AS STRONG AS A STEEL FIBER THE
SAME SIZE--AND CAN STRETCH  EXTENSIVELY WITHOUT BREAKING.  BIOPHYSICIST LYNN
JELINSKI AT CORNELL UNIVERSITY THINKS HUMANS COULD MAKE USE OF SUCH A STRONG
MATERIAL IN ANYTHING FROM SEATBELTS TO PARACHUTES.  OF COURSE, IT WOULD TAKE
AN ARMY OF SPIDERS TO PRODUCE ENOUGH SILK, SO JELINSKI IS ONE OF SEVERAL
SCIENTISTS WHO'D LIKE TO BE ABLE TO MAKE SPIDER WEBS WITHOUT THE SPIDERS'
HELP.

     Jelinski:"What we'd like to do is to find out the stucture. . .  what elements give it this nice
combination of elasticity and toughness and once we understand, we can make designer materials. . .
based on what we've learned from the spider." 

     JELINSKI AND HER COLLEAGUES WANTED TO LOOK AT ONE KIND OF PROTEIN,
CALLED ALANINE, THAT THE SPIDERS USED IN THEIR WEB WEAVING.  SO THEY FED THE
SPIDERS A SPECIAL KIND OF ALANINE THAT GLOWED ONCE THE SPIDER TURNED IT INTO
SILK. JELINSKI COULD EASILY MAP OUT THIS GLOWING ALANINE AND SHE FOUND THAT
THE PLACEMENT OF THE ALANINE WAS BY NO MEANS RANDOM.

     Jelinski: "what we've found that's so unusual is that the silk is highly oriented. The alanine are
folded . . . almost as an accordian, all squished together, where the sheets go up and down and up
and down. . . these are as oriented as in the highest performance fiber, kevlar."

     THE NEXT STEP IS TO FIGURE OUT JUST WHY THIS LATTICE OF ALANINE MAKES THE
SPIDER'S SILK SO STRONG.