Snippets from Science

• Women with a family history of breast cancer are 59% less likely to develop the disease if they breastfeed their offspring (according to Dr. Alison Stuebe of UNC Chapel Hill). The study failed to show such an effect in women without a family history of the cancer. The advantages of breastfeeding are many, including reducing the risk of infectious diseases in babies and decreasing the risks of heart attack, diabetes, and certain cancers in mothers. In addition, oxytocin, the so-called “love” hormone, is released in the mother during breastfeeding, which enhances bonding with the infant. (Archives of Internal Medicine, Aug. 10, 2009).

• Headline in the Pulse: “Meat Eating Plants Discovered at The Ridges Sanctuary!” No big deal! Pitcher Plants and Round-Leaf Sundews have grown in the sanctuary for years. Pitcher Plants have leaves shaped like a 3 to 4 inch cone resembling a “hooded pitcher.” Rainwater collects in the pitcher, and when insects crawl in they can’t crawl out because of the pitcher’s downward-directed hairs. The insect ends up in the rainwater, exhausts itself or drowns, and digestive juices released from the lining of the pitcher dissolve the insect and the plant absorbs its juices. In Southeast Asia there are pitcher plants the size of toilet-bowls that capture frogs and lizards, and even an occasional rodent. At the other end of this size spectrum, Sundew plants at the Ridges are very small, only an inch or less across, and their round, flat, leaves are attached to little stems arranged in a circular pattern at ground level. On the surface of the leaves are erect hairs tipped with a droplet of a sticky substance. When a wayward insect crawls over a leaf and makes contact with the sticky hairs, it becomes trapped as the leaf slowly folds around it. The insect is then digested and its substance becomes food for the plant. In swampy areas along the eastern shores of North and South Carolina there is an insect-eating plant called the Venus Flytrap. Endangered, these small plants have clamshell-like leaves that have several “trigger” hairs on their surface. When an insect crawls onto a leaf, contact with trigger hairs cause the two leaf-halves to slam shut in about a tenth of a second. The trapped insect is then slowly digested. (Burton and Stampp, Door County’s Wildflowers, 2005; Abigail Tucker, in Smithsonian Magazine, Feb., 2010)

• Chemicals called polybrominated diphenyl ethers (PBDES—now you know why there are so many acronyms in science) are used as fire retardants in furniture, textiles, bedding, carpeting, and electronics. After 30 years of use, we now learn that such chemicals may affect reproductive health and that “… 97% of Americans have detectable levels in their bodies.” Kim Hartley at the U. California, Berkeley, studied 223 lower income women. She found that “…each tenfold increase in the blood concentration of PBDES was linked to a 30% decrease in the probability of becoming pregnant each month.” This points up the problem with being chronically exposed to chemicals we once assumed were safe. Over years of use, science often discovers unexpected biological consequences of chronic exposure to such “safe” chemicals (e.g., PCBs, DDT, asbestos, chemicals in cigarette smoke, certain pesticides and herbicides, and the list will probably get longer). The Economist, Jan. 30, 2010)

• A school child defined memory this way: “My memory is the thing I forgot with.”