Doctor Yu, a professor of the School of Pharmaceutical Sciences of Wuhan University, is engaged in research about natural drug product and is experienced in modifying metabolic pathways to produce drugs using genetic engineering. Professor Yu told us that SAMe is an unstable molecule and it may be absorbed by other gut microbes. Therefore, it is merited further study that whether SAMe secreted in the gut could relieve depression. And he suggested that animal experiments in mouse models can be considered for follow-up if available.

     Professor Gan is a professor of the School of Life Sciences of Wuhan University. Her research focuses on the energy metabolism, biosynthesis of microorganism and genetic codon extension technique.
    Professor Gan pointed out that our chassis, Bifidobacterium longum, is anaerobic so that it is difficult to cultivate. Considering the unclear genetic background of Bifidobacterium longum, we finally decided to conduct our experiments in Bacillus subtilis, which is also Gram-positive but more convenient for gene editing.
    We asked Professor Gan about whether the genetically engineered bacteria would lack the raw material to synthesize SAMe, and she held the point that other gut microbes and food in the gut might supplement methionine for our genetically engineered bacteria. However, it merits consideration that the SAMe secreted by the engineered bacteria may be absorbed by other gut microbes.
    Professor Gan also believes that it is a good idea to construct our engineered bacteria as a drug pump in vivo that can produce other drugs in the future.