The pathogen theory behind AD, a predictive signature for TB, and growing spider venom for research. This week in Abstract Science.

Microbes & AD

(Scientific American, 3/21/16, Melinda Wenner Moyer)

Some scientists believe that Alzheimer’s disease may have a surprisingly simple trigger: tiny brain-infecting microbes. Their theory rests on the idea that in certain vulnerable individuals—such as those with the APOEε4 gene variant, a known Alzheimer’s risk factor—common microbial infections can infect the aging brain and cause debilitating damage. However, critics of the pathogen theory point out that much of the supportive human research does not establish cause and effect. This insightful piece in Scientific American explores both sides of the issue deftly.

The White Plague

(Science, 3/23/16, Kai Kupferschmidt)

One of the essential mysteries surrounding tuberculosis (TB) is who, among the millions infected with the bacterial infection, will actually get sick. Scientists may have found an answer: a set of 16 genes that is more active in people who will develop TB in the next one or two years than in those who are infected but stay healthy.To find a predictive signature, scientists took advantage of a large study of more than 6,000 young people at risk of TB who were followed in South Africa for at least two years. The researchers compared blood samples from 37 people who developed TB and 77 others who carried M. tuberculosis but remained healthy; they discovered 16 genes that were more active in the former group. They then tested how well the signature held up in another nine participants who had developed TB and 30 who didn’t. The test confirmed the predictive power of the gene signature. Ten other research sites validated the results.

Spider Farming

(Wired Science, 3/23/16, Sarah Zhang)

The venom found in deadly spiders is filled with proteins that can kill you but which also might make your stronger. Using synthetic biology, companies are taking genes from the venom protein of interest and growing them in yeast and bacteria. The vast amounts of protein material are being used to develop insecticides and drugs for epilepsy and stroke.

—Compiled by Senior Scientific Writer Regina McEnery