Bacteria harboring glycerol/diol dehydratase (GDH) encoded by the genes pduCDE metabolize glycerol and release acrolein during growth. Acrolein has antimicrobial activity, and exposure of human cells to acrolein gives rise to toxic and mutagenic responses. These biological responses are related to acrolein’s high reactivity as a chemical electrophile that can covalently bind to cellular nucleophiles including DNA and proteins. Various food microbes and gut commensals transform glycerol to acrolein, but there is no direct evidence available for bacterial glycerol metabolism giving rise to DNA adducts. Moreover, it is unknown whether pathogens, such as Salmonella Typhymurium, catalyze this transformation. We assessed, therefore, acrolein formation by four GDH-competent strains of S. Typhymurium grown under either aerobic or anaerobic conditions in the presence of 50 mM glycerol. On the basis of analytical derivatization with a heterocyclic amine, all wild-type strains were observed to produce acrolein, but to different extents, and acrolein production was not detected in fermentations of a pduC-deficient mutant strain. Furthermore, we found that, in the presence of calf thymus DNA, acrolein-DNA adducts were formed as a result of bacterial glycerol metabolism by two strains of Limosilactobacillus reuteri, but not a pduCDE mutant strain. The quantification of the resulting adducts with increasing levels of glycerol up to 600 mM led to the production of up to 1.5 mM acrolein and 3600 acrolein-DNA adducts per 108 nucleosides in a model system. These results suggest that GDH-competent food microbes, gut commensals, and pathogens alike have the capacity to produce acrolein from glycerol. Further, the acrolein production can lead to DNA adduct formation, but requires high glycerol concentrations that are not available in the human gut.

Measles is a dangerous and nasty disease caused by the measles virus. The virus spreads quickly from person to person, and there is no cure. A successful vaccine had almost completely eliminated the disease from America and Europe. Unfortunately, due to scare-stories and fake news, many people stopped getting the vaccine. This has allowed the disease to come back. Here we explain: () what measles is; () how the vaccine works; and () why the scare-stories are not true. WHAT IS MEASLES? Do you remember the last time you were sick? Maybe you had pain or a fever? Maybe every noise and touch felt horrible? Maybe you could not sleep, or you could not stay awake? You may have experienced these feelings a few times in your life, due to di erent infections. Measles is a particularly bad infection. It causes a high fever, a bad cough, red and itchy eyes, and a red, flat skin rash. If you are lucky, the symptoms kids.frontiersin.org September | Volume | Article |

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