Author: Alexander Patananan
Institution: UCLA
Date: February 2008
When you think about the lowly honeybee what comes to mind? Honey? Food? A little varmint that does nothing but sting you? To the average person, taking a look at this simple creature usually does not conjure up any sense of excitement or thrill. In fact, the most exciting thing about honeybees to a human may be chasing them around with a flyswatter or, better yet, spraying chemicals at them that typically leave you in worse condition than the bee. But, the honeybee, in addition to many other eusocial insects such as ants, possesses an amazing characteristic longevity. If you have ever taken a walk in a garden on a nice spring day, you probably have noticed hundreds and hundreds of honeybees buzzing around. These are usually the worker bees, which can live as long as 1 year. Now, this may not seem to be a very long time to you but consider the queen honeybee. Unlike the worker bees, the queen may live up to 47 times longer than the nonbreeding workers. This is on the contrary to other species whose lifespan declines as the frequency of reproduction increases. Although the exact reason for this dramatic difference in longevity is still not fully known, a great deal of research has been conducted addressing the phenomenon due to its obvious important to human life.
There are many factors that appear to increase lifespan. The first involves the repair of the telomeric ends of chromosomes by the enzyme telomerase. Telomeres are sometimes referred to as the protective caps of chromosomes, reducing homologous recombination at the ends. Studies have shown that as cells divide, these regions gradually breakdown. Over many rounds of cell division, these ends will have shortened to such an extent that cell division is halted. Slowing down the degeneration of the telomeres by the enzyme telomerase, which is produced in part by a gene called Tert, has been thought to maintain these regions for significantly longer periods. Another component of longevity may involve the gene forkhead box, sub-group O, which is more commonly referred to as FOXO. Like the telomeres, FOXO is also involved in apoptosis regulation, stress-response, and cell division, being associated with not only the insulin receptor cascade but also the c-Jun amino-terminal kinase cascade. Studies have shown that overexpressing FOXO in Drosophila melanogaster has the capability of increasing lifespan by over 50%.
In his paper, "Longevity in the honeybee (Apis mellifera): expression of telomerase and insulin signaling pathway genes in queen and worker bees," Eli David Hornstein from the North Carolina School of Science and Mathematics investigated the affects of the genes Tert and FOXO on longevity. Under various conditions, gene expression levels were calculated by quantitative real-time PCR. It was determined that queen bees produced more Tert and less FOXO than the worker bees. Furthermore, it was concluded that the reproductive status of the queen bee also had an effect on the expression of these two genes. To learn more about this fascinating topic of longevity, please consult Eli David Hornstein's paper in the latest edition of the Journal of Young Investigators.
Written by: Alexander Patananan
Published by: Konrad Sawicki