Stem Cells, Hummingbirds and Spider Silk

• Medical researchers have developed methods of creating new blood vessels, voice boxes, and windpipes (tracheae) to transplant into patients who have lost their own due to cancer or injury. Such advances result from the use of stem cells and bioengineering. In the case of windpipes (tracheae), stem cells are seeded onto a porous scaffold made to recreate the shape and size of the old windpipe. Stem cells from the patient’s bone marrow are grown on the scaffold until it becomes a replica of the original windpipe, which it then replaces. Blood vessels are grown in the lab by inducing sheets of stem cells to roll up and form tubes. These have been implanted in kidney patients to make dialysis more efficient. Predictions are that new replacement blood vessels could be mass produced within the next two years and various sizes stockpiled under refrigeration until needed. (Sources: Macchiraini et al, 2008, The Lancet, vol. 372, p. 2033; The Week, July 15, 2011)

• Hummingbirds were once thought to use their tongue to “sip” nectar into the mouth cavity, as we do when drinking through a straw. But recent research shows that the way hummingbirds drink is more complex. The tiny tongue, only a millimeter in diameter, is made up of two thread-like shafts covered with little hairs. When the hummer is feeding, the two shafts splay apart, and the opposing hairs curl outward as the tongue is submerged into nectar. Upon withdrawal, the hairs curl inward, trapping nectar, and the loaded tongue is retracted into the mouth cavity— all in about 1/20th of a second. In the mouth the hairs open up and unload their nectar for swallowing, and the tongue flicks back into the flower for another load. (Source: Audubon Magazine, July –August, 2011)

• When the Australian government considered imposing a carbon tax, 30 of the country’s climate researchers who supported the measure received death threats and abusive emails. A carbon tax is a tax imposed on entities, such as coal-fired power plants, that contribute large amounts of gases to the atmosphere that contribute to climate change (aka global warming). Scientists believe that record-breaking tornadoes, floods, and droughts will become routine weather events as the earth’s surface continues to warm. Jay Gulledge, a research director at the Pew Center on Global Climate Change, says “Climate change is a risk factor for extreme weather just as eating salty foods is as risk factor for heart disease.” One of the largest databases of natural disasters in the world is maintained by Munich Re, a global insurance firm. Peter Hoppe, of Munich Re, believes the warming trend is underway, and the increases in extreme climate events since 1908 “…can only be fully explained by climate change.” (Sources: Science, June 17, 2011; The Week, July 15, 2011)

• It’s well known that spiders secrete silk from the tip of their abdomens, but researchers in Britain discovered that tarantulas also secrete silk from their feet. Their discovery was a simple exercise in observation. They place tarantulas in a glass tank, shook the tank and turned it sideways, then observed nearly invisible silk threads that spiders deployed as they slid down the sides of the tank. In the movies, Spiderman shoots silk threads from his hands, a feat nature invented millions of years ago. (Source: Smithsonian Magazine, July/August, 2011)

• If you haven’t heard of krill, this is a good time to learn. These are tiny crustaceans (related to shrimp) that are at the bottom of the oceanic food chain. Thousands of animals, from whales to penguins to fish, depend on krill as a primary food source. If krill disappeared from the seas, the result would be catastrophic. The diminishing population of penguins across the west Antarctic peninsula has now been linked to an 80 percent drop in the krill population in the region. A biological oceanographer at Rutgers University feels that climate change may be involved. (Sources: Proceedings of the National Academy of Sciences, April 11, 2011; Science News, May 7, 2011)