Plant-derived lignans, consumed daily by most individuals, are thought to protect against cancer and other diseases 1 ; however, their bioactivity requires gut bacterial conversion to enterolignans 2. Here, we dissect a four-species bacterial consortium sufficient for all five reactions in this pathway. A single enzyme (benzyl ether reductase; ber), was sufficient for the first two biotransformations, variable between strains of Eggerthella lenta, critical for enterolignan Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

Diastereoselective Lewis acid-mediated additions of nucleophilica lkenest oN-sulfonyli mines are reported. The canonical polar Felkin-Anhm odel describing additions to carbonyls does not adequately describe analogousa dditions to N-sulfonyl imines.H erein, we describe the develop-ment of conditions to produce both syn and anti products with high diastereoselectivity and good yields. As tereoelectronicm odel consistent with experimental outcomesi sa lso proposed.[a] L.

Aims:The gut microbiota modulates dopamine levels in vivo, but the bacteria and biochemical processes responsible remain incompletely characterized. A potential precursor of bacterial dopamine production is 3-methoxytyramine (3MT); 3MT is produced when dopamine is O-methylated by host catechol O-methyltransferase (COMT), thereby attenuating dopamine levels. This study aimed to identify whether gut bacteria are capable of reverting 3MT to dopamine. Methods and Results: Human faecal bacterial communities O-demethylated 3MT and yielded dopamine. Gut bacteria that mediate this transformation were identified as acetogens Eubacterium limosum and Blautia producta. Upon exposing these acetogens to propyl iodide, a known inhibitor of cobalamin-dependent O-demethylases, 3MT O-demethylation was inhibited. Culturing E. limosum and B. producta with 3MT afforded increased acetate levels as compared with vehicle controls. Conclusions: Gut bacterial acetogens E. limosum and B. producta synthesized dopamine from 3MT. This O-demethylation of 3MT was likely performed by cobalamindependent O-demethylases implicated in reductive acetogenesis. Significance and Impact of the Study: This is the first report that gut bacteria can synthesize dopamine by O-demethylation of 3MT. Owing to 3MT being the product of host COMT attenuating dopamine levels, gut bacteria that reverse this transformation-converting 3MT to dopamine-may act as a counterbalance for dopamine regulation by COMT.

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