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New weapon against anthrax? Your tears

Don't cry, Brett Favre, your tears can help protect against all kinds of bugs -- just not NFL linebackers.
Don't cry, Brett Favre, your tears can help protect against all kinds of bugs -- just not NFL linebackers.Jonathan Daniel / Getty Images

Cry me a river and chances are it’ll be germ free. Tears aren’t just for telenovela actresses, departing baseball managers (I’m talking about you, Lou), and Brett Favre’s annual retirement cry.They do far more than lube your eyeballs, a fact illustrated by Saeed Khan, a researcher at the National Center for Toxicological Research in Jefferson, Ark. Khan, who is presenting his results Thursday at the annual meeting of the American Chemical Society, wanted to test how well lysozymes, an enzyme found in human tears and other biological fluids that attacks the cell walls of bacteria, could resist anthrax. Egg whites, like tears, contain lots of lysozyme. Sure enough, when Khan and his colleagues infected egg whites with an anthrax stand-in, the lysozyme in the egg white killed the spores. Spores were also inactivated when Khan added lysozyme to ground beef and milk. And it's not just tears that can do that, says Alexander M. Cole, associate professor at the Burnett School of Biomedical Sciences at the University of Central Florida. “Pretty much every wet area of your body” has antimicrobial powers, he explained. Rambo mucus in our airways dismantles germs. (In fact, back in 1922, Alexander Fleming, the man who discovered penicillin by accident, also got lucky when a drop from his runny nose fell into a bacteria-filled Petri dish and killed off the germs around it.) Semen may be transportation for sperm, but it also contains peptides, especially one called cathelicidn, that mow down bacteria in its path so those sperm have a clear swim to the egg. Sweat does more than keep you cool; it contains another peptide called dermcidin that attacks bacterial membranes. It’s effective against staph, for example. In addition to nasal fluid, Cole has extensively studied the cervical-vaginal mucus of the female reproductive tract and found that it isn’t just there to provide a happy environment for sex. It includes antimicrobial peptides that help fight off bacteria and viruses like HIV. Perhaps most surprisingly, even human urine appears to have germ-killing powers. There is evidence, Cole explained, that it contains a peptide called human beta defensin 1 that may help keep a urinary tract infection from reaching the kidneys. Best of all, Cole said, body fluids don’t fight germs in just one way. Various peptides attack different vulnerabilities so that germs cannot adapt and become resistant, the way they can to manufactured antibiotics. That’s why body fluids from people and animals is now being researched in hopes of making new antimicrobials. We are assaulted by germs constantly. In fact, it’s estimated our bodies have more germs on them and in them, than we have cells. Sometimes, of course, those defenses are overwhelmed and we wind up doubled over on the bathroom floor but it’s time we give a little respect to all those sticky, runny, watery emissions we like to pretend don’t exist. To read more Body Odd posts, click here. You can also find us on Twitter and on Facebook.