Science Concentrates SYNTHESIS
C R E D I T: S H UT T E RSTO CK
C&EN Global Enterp 2019.97:5-5. Downloaded from pubs.acs.org by IOWA STATE UNIV on 01/31/19. For personal use only.
Laser powers new flow photoreactor Visible light–promoted reactions offer industrial chemists simple yet unique routes to valuable pharmaceutical compounds. But the chemists have struggled to run these powerful transformations on a large scale because it is hard to get light where it needs to go in a reactor. For example, lamps and light-emitting diodes can penetrate only a few millimeters into a solution. To address this issue, chemists have turned to tubular flow, pumping their reaction solutions through spindly tubes for maximum exposure to light. Now, researchers at AbbVie report a new solution to the light-penetration problem: high-powered lasers (ACS Cent. Sci. 2019, DOI: 10.1021/ acscentsci.8b00728). The team hooked up a laser to a beam expander and fiber-optic cables to irradiate a continuous stirred-tank reactor (CSTR)—a standard reactor used in industry. This setup avoids heating the reaction, which is an issue for large-scale tubular flow because chemists must point an array of lights at the reaction. The tank reactor also allowed chemists to use insoluble reagents that aren’t tolerated in typical flow systems because they clog the lines. But the main advantage, the authors say, is the increased penetration of light into the reaction vessel. They found that the rate of reaction, and thus reaction yields and throughput, increased as the intensity of the light source increased. The team achieved reaction rates of kilograms of product per day in a 100 mL reactor. Ian W. Davies, director of Princeton University’s Catalysis Initiative, calls the setup a creative adaptation of CSTRs and a valuable addition to photoredox flow technology.—TIEN
NGUYEN
Some gut microbes may protect against milk allergies.
MICROBIOME
Gut microbes may protect against food allergies Mice develop milk allergies when given fecal transplants from allergic babies The team analyzed the bacterial conAn experiment involving mouse guts and tents of the donor feces and found one baby poop may help us understand why species, Anaerostipes caccae, was less desome infants develop food allergies. tectable in the allergic baby stool. Bacteria Researchers led by Cathryn Nagler at the University of Chicago made mice aller- like A. caccae have been tied to keeping the immune system in check in the small gic to milk simply by giving the animals a intestine, Nagler says. fecal transplant from human babies with Nagler says her team is trying to figure the allergy (Nat. Med. 2019, DOI: 10.1038/ out why A. caccae is missing in children s41591-018-0324-z). The findings suggest with milk allergies. Is it the absence of that particular classes of gut bacteria may bacteria that causes the allergy, or does protect mice, and people, from developing the allergy somehow lead to the loss of food allergies. beneficial bacteria? The experiment has garnered praise. Nagler thinks the ability to give mice “It’s shocking, to be honest,” that transfera milk allergy through fecal transplants ring the microbiome gave mice an allergy, says allergist Kari Nadeau at Stanford Uni- will provide researchers with a model to help them investigate possible therapies. versity School of Medicine. But giving allergic infants transplants of Previously, Nagler and collaborators feces from healthy babies is not on the compared the microbiomes of healthy and horizon, mainly because researchers still milk-allergic infants and found “an enordon’t know if a friendly bacterial mous difference,” she says, “even O species in one gut could cause at just four to five months of age.” In the new study, the scientists O– disease in another. Instead, Nagler says, her team wants to test restorgave mice feces from formula-fed Butyrate ing metabolites from the missing infants who were either allergic bacteria. For A. caccae, that metabolite is to milk or were not. The researchers then butyrate, which is used by intestinal cells fed the animals their normal food, but as a source of energy. included baby formula, hoping to incen“I think it’s important to keep in mind tivize the bacteria to colonize the mice’s that it’s not going to be a single bullet you intestinal tracts. can use to treat food allergy,” says allergist When the scientists then fed the mice Supinda Bunyavanich at the Icahn School an allergy-causing milk protein, the mice of Medicine at Mount Sinai. Gut bacteria receiving the allergic infant transplants act in communities, she says, and the differshowed signs of an allergic reaction. The ent species may influence how the immune mice receiving the healthy transplants system acts.—MEGHA SATYANARAYANA did not. JANUARY 28, 2019 | CEN.ACS.ORG | C&EN
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