Blogs / Discoblog

Could all those furry lab rodents soon be replaced with insects? Possibly, as Irish scientists discovered while testing how the immune systems of insects fights off a bacterial or fungal infection. It turns out insect cells respond to infections the same way mammals’ cells do, producing similarly structured enzymes to kill off intruding microbes.

When National University of Ireland’s biologist Kevin Kavanagh looked at immune cells in insects, and compared them to the white blood cells in mammals, he found that they both fought the invading pathogen through a similar chemical attack—which makes sense given that mammals and insects have immune systems that are 90 percent identical.

The researchers believe that substituting moths in the initial testing of new antimicrobial drugs could reduce the demand for mice by 80 percent. Reuters reports:

“It is now routine practice to use insect larvae to perform initial testing of new drugs and then to use mice for confirmation tests,” said Kevin Kavanagh, a biologist from the National University of Ireland, who presented his research at a Society for General Microbiology meeting in Edinburgh.

“This method of testing is quicker, as tests with insects yield results in 48 hours whereas tests with mice usually take 4 to 6 weeks. And it is much cheaper too.”

The cost savings of switching to bugs would be enormous: A caterpillar costs 16 to 32 cents, while a mouse chews up between $80 to $130 per experiment. Kavanagh tested 700 new drugs using a relatively small number of insects—the same research would have needed 14,000 mice.

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Image: flickr/ CameraShyMom

Could milk from mice be the next key ingredient in infant formula? Perhaps…if researchers can find an efficient way to milk them, that is.

Apparently, getting the tiny rodents to produce lactoferrin, a protein found in human breast milk, wasn’t a problem, once the Russian scientists added a few human genes to the mice’s genome.

Mouse milk naturally has a higher concentration of proteins than the human stuff, so when the mice began producing human milk protein, they made a lot of it. In fact, the fuzzy creatures produced up to six ounces of lactoferrin per quart of milk, as opposed to the measly four to five grams per quart pumped out by humans.  The lactoferrin in breast milk is important because it shields babies from infection as their immune systems form.

Mass production of human milk protein could allow the substance to be used in synthetic infant formula. Today, formula is largely made up of protein from soybeans or cow’s milk, and although the subject remains controversial, some experts say it does not provide babies with the same health benefits of human milk.

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Police in India have found an unlikely solution for a mouse problem: rats. Almost all over the state of Haryana, mice have been getting into just about anything they find appetizing, including official court documents, food supplies intended for people, and even the fiber sacks used to store confiscated narcotics. Landmine removal efforts near the border with Pakistan were jeopardized in 2002 by rodents moving anti-personnel mines from their mapped locations.

On a tip from a local citizen about a month ago, the police in Karnal, a district with a particularly high mouse infestation, bought two domesticated albino rats and released them into problem areas. It worked, the police said, “like magic.” They have since been releasing the rats every night into the storage room of official documents, and the mice have “just disappeared.”

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Many people (Discoblog editors included) who crave that mid-afternoon cookie fix may joke that they have a sugar addiction, but now scientists have made it official. Researchers at Princeton University report that sugar-loving mice demonstrate all three criteria of addiction: increased intake, withdrawal, and cravings that lead to relapse.

Previous work has shown that mice deprived of food for several hours and then allowed to binge on sugar water (with concentrations similar to that of soft drinks) soon developed addictive behaviors. Sugar intake causes the release of dopamine in the brain, a reward chemical. After a month of sugar binging and increased dopamine levels, the rats’ brains developed fewer dopamine receptors and more opioid receptors—changes similar to those observed in mice on cocaine and heroine.

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If you want to be leggier, consider moving to Florida. It might even work if your parents have average-sized limbs. New research has found that DNA isn’t the only route to long legs: Warmer temperatures can also lead to longer limbs by helping cartilage grow, at least in mice.

Researchers raised baby mice in cold (45F), normal (70F), or warm (81F) temperatures for about two months. The mice raised in warmer temperatures grew longer tibias and femurs (leg bones), and metatarsals (”toes”). The researchers say the effect may be partly explained by increased blood flow under warmer conditions, which promote growth of the cartilage capping the ends of long bones. However, this doesn’t fully explain the results, and they believe temperature also affects other biological mechanisms, like the expression of proteins.

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