Alfalfa and bacteria sounds like a nightmarish hippie salad from the 1970s, but according to scientists at Iowa State University, it’s the recipe for growing food crops on Mars to feed hungry astronauts on future missions. Martian soil is so poor in nutrients that most crops won’t grow, but by first growing alfalfa plants, which thrive in a nutrient-limited soil like that found on Mars, their biomass could become biofertilizer to grow later crops of turnip, radish, and lettuce. Likewise, the briny water of the red planet could be desalinated with a form of marine Synechococcus cyanobacterium. Yum! PLOS ONE

For fans of structural biology and immunology, it doesn’t get much better than this: Two companion papers showing the first high-resolution snapshots of one of the most colossally important molecules in human health, the B cell receptor. Almost every vaccine on the market today, including those for COVID-19, work by inducing immunity after they bind to B cell receptors. Understanding these key structures at the atomic level may help design new antibody-based therapeutics for many diseases. The first paper, by a group at Westlake University in Hangzhou, China, uncovers the organizational principles of the B cell receptor. The second paper, from researchers at Harbin Institute of Technology in China, reveals the structural basis for how B cell receptors are assembled and triggered. Science

The next generation of wearables promises to go beyond measuring simple heart rates or step counts by plugging directly into the body’s metabolism through sampling the sweat on our skin. Sounds gross? What if we told you that monitoring the levels of nutrients, fats, amino acids, metabolites, and vitamins in your sweat could pave the way toward “precision nutrition,” where those biomarkers inform personalized nutritional recommendations in real time throughout the day? Designing electrochemical monitors is easy enough, but the challenge is designing one you can comfortably wear all day long that works continuously—and not just when you are sweating profusely in exercise. Researchers at Caltech are reporting they designed a solution to the challenge: a wearable patch based on laser-engraved graphene coated with a polymer technology known as “artificial antibodies.” They call their device NutriTech and report it can be integrated into a wristwatch and monitored with an app. Nature Biomedical Engineering

Researchers at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, and Cedars-Sinai Medical Center in Los Angeles have developed a blood test to detect the body’s response to intestinal bacteria that leave the gut where they normally reside and invade other tissues. When gut bacteria like Collinsella, Bifidobacterium, Lachnospiraceae, and Ruminococcaceae translocate, they can elicit immune responses and exacerbate inflammatory bowel disease, nonalcoholic fatty liver disease, and cancer. They can also affect cancer immunotherapy and chemotherapy. The new method samples blood serum and quantifies molecules known as immunoglobulin G (IgG), the most abundant antibody in the bloodstream, which enables the researchers to quantify the body’s inflammatory response to the straying bacteria—something they say could to lead to better, more personalized future treatments. Science Translational Medicine

People in the rewilding movement take note: Anthropologists at the University of Manchester and at Maastricht University have demonstrated that for early humans, chewing required effort—imagine a lot of fibrous veggies and gamey meat—and actually cost a significant amount of their total daily energy. For modern humans, mastication is just a small part of our daily energy expenditure because of all the soft, packaged foods we eat—domesticated and tenderized meat, refined vegetables, and highly processed foods. To show the effect, researchers placed 21 people in hooded chairs and measured oxygen consumption, CO2 production, and masseter muscle activity for 30 minutes while they chewed tasteless, odorless gum. The chewing in fact raised their metabolic rates by 10–15 percent, with stiffer gums costing more energy to chew. “Understanding the energetic cost of chewing may provide a novel insight into dietary changes throughout human evolution,” the researchers write. Science Advances

The ventilated hood system at Maastricht University used to measure oxygen consumed and carbon dioxide produced during activities such as chewing. Amanda Henry

A group of U.K. and U.S. sports doctors who work with a number of European and American sports teams, including the Toronto Raptors, the San Francisco 49ers, the Dallas Mavericks, and Newcastle United are calling for greater scrutiny and oversight of “drip bars,” an IV hook up spot (mobile spots also available) where a growing number of professional athletes go. They are part of a growing trend popular with high profile entertainers, CEOs, and everyday people who go for everything from a simple rehydration drip (saline) to all sorts of menu items with various health claims like cocktails promoted as immune boosters, anti-aging treatments (includes NAD+ and a glutathione push), energy boosters, or hangover cures. Administering vitamins, amino acids, electrolytes, and other nutrients to athletes is nothing new, and for some sports, like desert ultramarathons, IV fluids can be essential. But in their editorial, the doctors point out the sparse evidence supporting the broader claims drip bars make—like their products can counter fatigue or quicken recovery. Professional sports governing bodies and players associations should take a closer look at the trend within their sports, provide guidance, and warn players of any potential risks, the doctors say, calling for “food first and no needle” in an editorial this week. British Journal of Sports Medicine

Researchers at Rockefeller University in New York and Boston University in Massachusetts have discovered a molecular oddity in one type of mosquito that probably helps them detect human odors. People give off lots of smells that mosquitoes detect through olfactory neurons in their antennae. Each neuron was thought to express a specific type of odor receptor molecule on their surfaces—but only one. Scientists have tried deleting these receptors from the mosquito genome to mask human smells to mosquitoes, but the bugs still found a way to bite. Surprisingly, it turns out that female Aedes aegypti mosquitoes, the primary pest that transmits dengue fever, yellow fever, West Nile virus and Zika, have an unforeseen genetic failsafe. Their olfactory neurons express multiple odor receptors, a redundancy that likely makes their olfactory systems more robust and could explain why it’s so hard to stop them from biting, even with bug spray. Cell