Episode 1: Science News

This week in the Petri Dish news:

A Sting In The Tale
Symbiosis is the process whereby two species evolve to live together in close and long-lasting interactions. Many people confuse symbiosis with mutualism, which is a type of symbiosis where the interaction is mutually beneficial, but parasitism (where one species benefits but the other one suffers, like tapeworms and their hosts) and commensualism (where one benefits but the other is unaffected, like vines living on trees) are also types of symbiosis.

You don't often get interactions more long lasting or intimate than incorporation of one species into another's genome, though. A group from the National Center for Scientific Research (CNRS) in Tours, France has found Braconid wasps have incorporated a Nudivirus into its genome. This isn't all that uncommon - it's the way retroviruses like HIV work. But unlike most cases, both the virus and the wasp have benefited. The virus is given somewhere warm and safe to live, and in return it gives the wasps the toxins they need to sting things.

The virus probably used to parasitise the wasps a few million years ago, and has since been fought to a standstill and come to benefit the wasp.

http://sciencenow.sciencemag.org/cgi/content/full2009/212/2

What's Not Hot in 2008 - The Climate

2008 was a cool year, temperature wise. Climatologists from NASA Goddard Institute for Space Studies (GISS) in New York City found that 2008 was the coldest year since 2000. But don’t get too excited because the report found that 2008 was still pretty damn hot. It was the ninth warmest year since records began in 1880. The cool climate was probably caused by a strong La Niña that was around in the first half of the year. La Niña and El Niño are opposite stages in the natural fluctuation in Pacific Ocean temperatures. La Niña is the cool phase. El Niño is the warmer phase, which typically follows within a year or two of its cooler cousin La Niña.

http://geology.com/nasa/nasa-maps-graphs-global-warming.shtml

Got Milk? Calcium Beats Cancer

Women with a higher intake of calcium have a lower risk of cancer. And both men and women with high calcium intakes have lower risks of colorectal cancer and other cancers of the digestive system. The findings are published in the February 23 issue of Archives of Internal Medicine. The research team analyzed data from 293,907 men and 198,903 women. The participants took a food frequency questionnaire between 1995 and 1996 reporting how much and how often they consumed dairy products and supplements. The results from that questionnaire were then linked with state cancer registries to identify new cases of cancer through 2003. Calcium intake was not associated with total cancer rate in men but was in women. According to the study to avoid an increased risk of cancer women should consuming 1,300 milligrams per day. One glass of milk gives around 300mg of calcium.

Yikyung Park (2009), Archives of Internal Medicine, 169(4):391-401.

http://archinte.ama-assn.org/cgi/content/abstract/169/4/391?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=calcium+cancer&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT