The week’s most astounding developments from the neobiological frontier.

October 20, 2022

Exercise and longevity after age 65

Your workout routine in your 20s may still be working for you at age 40, but by the time you reach your mid-60s, you might want to consider rethinking your training habits—but that doesn’t mean you should stop. A new study published this week demonstrates that longevity benefits after age 65 can be obtained by moderate to vigorous aerobic activity combined with strength training. (Federal physical activity guidelines also recommend balance training.) Researchers at the U.S. Centers for Disease Control and Prevention compared physical activity to deaths among 115,489 people who self-reported their exercise in federal health survey interviews from 1998–2018. The study found that 10–300 minutes of moderate to vigorous aerobic activity per week and 2–6 strength training sessions per week were both associated with lower all-cause mortality. The maximum benefit, including for people 85 and over, came from doing both. Never stop! JAMA Network Open

Black Death, human evolution, and autoimmune disease susceptibility

Untimely death is an ultimate driver of evolutionary selection, and scientists have long speculated that massive disease outbreaks of the past may have shaped human genetics. Perhaps no outbreak looms as menacingly in the human psyche as the Black Death, a runaway plague of Yersinia pestis in the mid-14th century that killed up to half the population of Europe. It forever altered culture and economics, and now there’s solid evidence it shaped the human immune system as well. A new study from McMaster University and the University of Chicago looked at 206 DNA samples extracted from the remains of people who died before, during, and after plague hit London and Denmark. They found evidence of selection for 245 DNA variants during the plague, including some associated with genes that appear to enhance the cytokine immune response to the bacterium. On the flip side, those same protective variants also overlap with genetic susceptibility to autoimmune diseases today. Nature

Researchers extracted DNA from the remains of people buried in the East Smithfield plague pits, which were used for mass burials from 1348–1349. Museum of London Archaeology

3D models of tumors will transform treatment

Cancer treatment is something of a poster child for precision medicine. The heterogeneity of human tumors has long demanded personalized surgery and radiation therapy plans, which are worked out by treatment teams in advance of treatment. In the modern era, uncovering specific genetic drivers of disease has led to the development of checkpoint inhibitors and other targeted therapies like Gleevec and Herceptin. But precision medicine isn’t always molecular. Five years ago, supercomputing pioneer Larry Smarr created a 3D model of his own colon prior to undergoing surgery to address his inflammatory bowel disorder. That same virtual approach is going to revolutionize cancer treatment, according to researchers at the National Cancer Institute in Rockville, Maryland, the Jackson Laboratory for Genomic Medicine in Farmington, Connecticut, and the Terasaki Institute for Biomedical Innovation in Los Angeles. In a perspective this week, they describe how 3D patient tumor avatars (3D-PTAs) will accelerate and improve cancer treatment. Cancer Cell

The neurobiology of comfort food

A fine chef a proto.life editor Jason Bardi once knew used to refer to a Turkish saying that good taste is learned. This is backed up, at least partly, by neuroscience. Studies showing that bad tastes are indeed learned—exposure to toxins in food drives associative learning in the brain, which causes animals to avoid similar tasting foods in the future. Now researchers at the University of Tennessee have shown that familiar, inconsequential, and otherwise good tastes change the brain as well. Imaging the brains of mice allowed to freely sip different tasting liquids, they observed the activity of taste-responsive neurons in the gustatory cortex greatly decreased as the animals became familiar with tastes. Could this brain-calming sensory habituation explain why comfort food is so tasty—because you don’t have to think about it? Current Biology

Ultra-compact spectrometer fits on a human hair

Spectrometers are one of the most common types of analytical tools used in chemistry and biology. Typically benchtop instruments, they blast samples with specific wavelengths of light and see how the samples absorb the light to measure things like the concentration of specific molecules in the samples. Now researchers at Aalto University in Espoo, Finland, have designed a spectrometer so small it could fit on the end of a human hair. It has a footprint of about one-sixth by one-hundredth of a millimeter and works in the spectrum of visible light, something that has never before been accomplished on such a small scale. Science

An image of the new human hair-sized spectrometer embedded on a chip small enough to fit on a finger. Oregon State University

You shark my back, I’ll shark yours

We do so love the resourcefulness of animals in the wild. A study this week from the University of Western Australia shows that when large, open-sea fish are infected with parasites, one strategy they use to self-treat their affliction is to scrape their backs on the skin of sharks to slough off the parasites. Smaller fish however—ones the researchers characterize as “bite-sized”—avoid this behavior. And for obvious reasons! Never let it be said that fish are stupid. The researchers point out that declines in shark populations in the world’s open seas could have much larger reverberations on other ocean wildlife like rainbow runner and yellowfin tuna by limiting their interaction with sharks and preventing them from scraping off parasites. PLOS ONE

A rainbow runner scraping on a blue shark at Ascension Island. Christopher D. H. Thompson, CC-BY 4.0