A Mosquito’s Characteristic Buzz and Vinblastine

• Insects tend to fly at two speeds: the escape (or takeoff) speed and the cruising speed. A large dragonfly, for example, maintains a cruising speed of about 16 mph, but its escape speed is closer to 35 mph. Cruising speeds of insects vary widely: a green lacewing cruises at 1.3 mph, a white cabbage butterfly at 5.6 mph, a bumblebee at 11 mph, and a horsefly at 31 mph. Rate of wing flapping also varies, but in general, the smaller the insect, the faster it flaps its wings. Honeybees flap 190 times a second, while a really tiny midge with a wingspan of only eight-hundredths of an inch beats its wings 1,047 times a second (“microflaps?”). A mosquito flaps its wings 600 times a second, the flapping causing the characteristic buzz.

The relationship between an insect’s size and wing speed also holds true in birds. Large birds, such as egrets and sandhill cranes, flap their wings about twice a second, while the tiny ruby-throated hummingbird manages 53 beats a second. (Waldbauer, 2012, How Not to Be Eaten, U. of California Press)

• Squirrel monkeys naturally lack a gene that, in monkeys with normal color vision, results in the production of a protein in retinal cells that allows their eyes to distinguish between red and green. When researchers injected normal genes producing this protein into the eyes of two adult squirrel monkeys, their eyes began to produce the protein, and the monkeys were then able to see red and green. Although there are many examples where gene therapy failed to correct an abnormal condition, in this case the approach worked. (Mancuso, et al, 2009, Nature, Vol. 461, Sept. 16, 2009)

• Proteins in animals and plants are constructed of chains of about 20 molecules called amino acids. In 1970 scientists found amino acids in the Murchison meteorite, which landed in Australia. Last August researchers found the building block molecules of DNA inside space rocks that landed in Antarctica. Because these two kinds of molecules are associated with life on this planet, there is reason to believe that somewhere in the universe there are other celestial bodies that support living things. (ScienceNews, April, 2012)

• Here in Door County, one of our earliest floral treats is the appearance of ground cover made up of the blue-violet flowers of Vinca minor, a species in the periwinkle family. What most people don’t know is that a chemical produced by this group of plants is, and has been, a key drug in cancer chemotherapy.

In 1952 a visitor to Jamaica sent 25 leaves from Vinca rosea, to a Canadian researcher who studied diabetes. In Jamaica a tea was made from these plant leaves to treat diabetes. The researcher who received the leaves had retired, so he gave them to his brother, Dr. Robert Noble, at the University of Western Ontario. When he tested an extract of the leaves on animals, there was no effect on diabetes, but the extract profoundly reduced white blood cell counts. His group then isolated the active molecule and named it vinblastine, and later Noble won the Nobel Prize for his discovery.

Today we know that vinblastine and other periwinkle drugs (e.g., vincristine) disrupt the thread-like microtubules that are required for cell division to occur. Without microtubules, cancer cells cannot reproduce themselves. Chemotherapy today usually involves using one of the Vinca drugs along with two or three other anti-cancer drugs. Anti-cancer drugs are potent poisons of cell division, and since cancer cells are the most rapidly dividing cells in a patient, the goal is to kill all the cancer cells without fatally poisoning the patient. Thousands of people are alive today because of Dr. Noble’s work. (Wright, J.R., 2002, Canadian Med. Assoc. Journal, Dec. 10, vol. 16, #12; also author’s sources)