"Feed a cold, die of hunger," or so the adage goes. But fruit fly experiments suggest that sleep may be a better remedy.
A microbial-fighting protein helps control the number of vegetables and, as the fruit flies, the researchers report on February 1 Science. This is evidence that sleep accelerates the recovery of the disease, they conclude.
"Finally we have a very clear connection between being asleep and fighting an infection," says sleep researcher Caltech Grigorios Oikonomou, who did not participate in the work. This link was hinted but never formally demonstrated, says Oikonomou, who co-authored a comment on the study on the same theme as Science.
Researchers at the Amita Sehgal laboratory at the Faculty of Medicine of Perelman of the University of Pennsylvania have made the discovery when looking for genes that control sleep. His team has sought proteins that, when produced excessively, will cause Drosophila melanogaster The fruit flies to sleep more. After combing more than 8,000 overproductive proteins, researchers found only one who released flies.
Fly with an overabundance of that protein, produced from nemuri Gene, he took more nuances during the day and slept more and more in the middle of the night. The strong blows of a device called "the hammer" woke up only 18 percent of these Nemuri-overproducing flies in the middle of the night but woke up more than 94 percent of normal flies, discovered Sehgal's team. The flies that lacked Nemuri revealed more easily than the normal flies when the investigators ignited or turned off lights in the tubes where the flies of the fruit slept.
The Sehgal team discovered that Nemuri is similar to fish proteins known as antimicrobial peptides, short proteins or protein bits that can kill microbes. In the tests of the effect of Nemuri on two types of bacteria, the protein killed the bacteria in laboratory dishes and, when overproduction, helped the bacterial infected fruit flies to survive longer.
The power of protein song, and not its antimicrobial activity, can be the one that actually fights the infection. The flies did more Nemuri not only when they were sick, but also when they had sleep deprived and under other types of stress. "The dream helps to fight against these challenges," says Sehgal. Nemuri may not be so important for daily sleep, except to help the flies to sleep at night
A double role of killing bacteria and provoking sleep is new for antimicrobial peptides, says Robert Hancock, a microbiologist and immunologist at the University of British Columbia in Vancouver. "But I'm not impressed," he says, "because peptides do many things."
Antimicrobial peptides are generally not as good for killing microbes in animals, however, says Hancock. Instead, peptides help regulate the immune system to perform a variety of tasks. It is possible, however, that mammals, including humans, who have more than 100 antimicrobial peptide genes, may have antimicrobial peptides that induce sleep during the disease.
"Produce an animal to sleep and concentrate all its resources in the fight against infection is useful to harbor the defense," says Hancock. Or as an Irish proverb says: "A good laugh and a long sleep are the best heals of the doctor's book."