Microbes for growth

Childhood malnutrition can cause developmental delays, cognitive impairment, susceptibility to infections, and permanently stunted growth. It is also responsible for one-third of childhood deaths worldwide.

Now, three new studies published in February suggest that manipulating the gut bacteria of nutritionally deprived children may help to protect them from the usual health effects.

In one study, published in Science, researchers planted gut bacteria from both healthy and malnourished children into the guts of mice bred to be germ-free. Despite consuming the same amount of calories, the mice that were colonized with bacteria from healthy children grew bigger than those colonized with bacteria from malnourished children.

A separate team of researchers in France, also publishing in Science, found that chronic malnutrition in mice resulted in growth hormone resistance that stunted growth. But they were able to eliminate growth hormone resistance by colonizing undernourished mice with a strain of the bacteria Lactobacillus.

In a third study, published in Cell, researchers compared the growth of germ-free mice with that of mice colonized with the gut bacteria of malnourished children. They discovered the bacteria-colonized mice grew bigger when they received sialic acid, a sugar present in milk, but the germ-free mice did not. They concluded that growth may be promoted by the byproducts released when bacteria consume sialic acid.

The researchers still need to determine whether humans would experience the same results as the mice in these experiments. If so, new probiotic food additives, once tested for safety, could help ensure fewer children suffer the effects of undernutrition.

Poison painkiller

The bite of a Peruvian green velvet tarantula is toxic. But Australian researchers want to use the venom to help chronic pain sufferers. The researchers discovered the tarantula’s poison can cause a chain of special amino acids to bind to the membranes of nerve cells and inhibit pain-related signals.

The research, presented at the Biophysical Society’s 60th Annual Meeting in February, could lead to a new generation of pain relievers more powerful than morphine but without the side effects and addictive properties. —J.B.

Bat lessons

Bats carry over 100 viruses, including Ebola and Middle East respiratory syndrome. Yet they never get sick from these pathogens, some of which are lethal to humans. A team of Australian researchers may have discovered an answer to this puzzle that could lead to new ways of protecting people from deadly infectious diseases.

The researchers, whose study was published in the February edition of Proceedings of the National Academy of Sciences, discovered that although the human immune system only activates in response to an infection, a bat’s immune system is switched on all the time—a condition that would be toxic for humans.

When immune cells detect an invading virus, they release proteins called interferons that prevent the virus from replicating and fire up the entire immune system. The scientists were surprised to find that bats have only three interferons: Humans have four times as many.

Clues from these bat immune system oddities could help scientists learn how to produce similar immunity in humans, perhaps providing a defense against deadly diseases like Ebola. —J.B.