Human Pathogen Killing Corals in the Florida Keys

The team's findings have just been published in the peer-reviewed open access journal PLoS ONE.

Kathryn P. Sutherland, associate professor of biology at Rollins College, and her research collaborators, Associate Professor of Environmental Health Science Erin K. Lipp and Professor of Ecology James W. Porter of the University of Georgia, have known since 2002 that the bacterium that killed coral was the same species as found in humans. "When we identified Serratia marcescens as the cause of white pox, we could only speculate that human waste was the source of the pathogen because the bacterium is also found in the waste of other animals," Sutherland said.

In order to determine a source for the pathogen, the research team collected and analyzed human samples from the wastewater treatment facility in Key West and samples from several other animals, such as Key deer and seagulls. While Serratia marcescens was found in these other animals, genetic analyses showed that only the strain from human sewage matched the strain found in white pox diseased corals on the reef. The final piece of the investigative puzzle was to show that this unique strain was pathogenic to corals.

With funding from Florida's Mote Marine Laboratory "Protect Our Reefs" grant program, Sutherland, Lipp and Porter conducted challenge experiments by inoculating fragments of coral with the strain found in both humans and corals to see if it would cause disease. The experiments were carried out in a laboratory in closed seawater tanks to eliminate any risk of infection to wild populations of corals.

"The strain caused disease in elkhorn coral in five days, so we now have definitive evidence that humans are a source of the pathogen that causes this devastating disease of corals," Sutherland said.

"These bacteria do not come from the ocean, they come from us," said Porter. Water-related activities in the Florida Keys generate more than $3 billion a year for Florida and the local economy. "We are killing the goose that lays the golden egg, and we've got the smoking gun to prove it," Porter said.
Read more

Sticky Business: Video Shows the Right Way to Extract Silk Glands from a Black Widow Spider

 Researchers illustrate a delicate method that could boost research into artificial spider silk—a material that is stronger than steel

Dissecting a black widow spider to get its silk glands seems like a task fraught with peril. Luckily, for anyone who dares, now there is video from scientists to show you how it's done.
Research labs do not want the silk glands of these infamous spiders for some kind of bizarre trophies. Spider silks are stronger than steel, and scientists across the globe are racing to develop synthetic fibers mimicking these silks for commercial, military and industrial applications, says biochemist Craig Vierra at the University of the Pacific in Stockton, Calif.
These fearsome arachnids—whose venom is 15 times stronger than a rattlesnake's—were chosen because "female black widow spiders have very large abdomens, making it very easy to isolate the silk-producing glands," researcher Coby La Mattina, also at Pacific, says as she narrates the video. As to why these researchers chose to make the video, "oftentimes the glands rupture during dissection. There are also certain anatomical structures that are difficult to isolate," Pacific researcher Tiffany Tuton-Blasingame says. "Visual demonstration is critical for a good dissection."
The scientists collect western black widows (Latrodectus hesperus) from wood piles, bushes and garages—the spiders' habitat is western North America. "When you knock them off their webs, they'll roll up and play dead, so they're really easy to scoop up," Vierra explained in a phone interview.
The black widows are anesthetized with carbon dioxide gas for 10 minutes. "While attempting this procedure, it's important to wear two pairs of gloves until the spider fangs are removed," Pacific graduate student Yang Hsia says during the video. As deadly as their venom is, their bites are usually not fatal, especially to adults, because they only inject small doses of venom—and like most spiders, black widows prey on insects.
After the researchers knock each spider out, they use scissors to cut the spider in half, snipping off the black widow's abdomen in the five minutes before the anesthesia wears off. (These procedures were approved beforehand by the Institutional Animal Care and Use Committee.)
The scientists then pin the abdomen down on a dissecting dish and use microscissors to cut out an opening. The abdomen is immersed in a special dissecting fluid cocktail of ingredients detailed by the researchers. The exoskeleton is peeled back with forceps, and any fat and eggs are scraped away to expose the seven distinct silk-producing glands. The researchers recommend these glands be removed in a specific order that makes it easier to get all of them out safely. The glands are then flash-frozen in liquid nitrogen and stored at minus 80 degrees Celsius.
The glands in western black widows each produce different kinds of silk: The major and minor ampullate glands manufacture dragline and scaffolding silk; the tubuliform gland synthesizes egg case silk; the aggregate gland makes glue silk; the aciniform gland synthesizes prey wrapping and egg-case threads; the pyriform glands produce silk that sticks onto surfaces; and the flageliform has an unclear function in this species. After scientists extract these glands they can analyze which different genes are expressed or which proteins genes make as well as clone these genes into bacteria and yeast to generate recombinant proteins for artificial silk fiber production, Vierra says.
Read more