MUC5AC and obesity due to melanocortin 4 receptor deficiency: In contrast, A. muciniphila grown under mucin-depleted conditions upregulated the genes involved in glycolysis, energy metabolic pathways, and 79 genes encoding extracellular protein candidates including Amuc_1100, which, in turn, reduced obesity and improved intestinal barrier more efficiently than administration of A. muciniphila grown under mucin-containing conditions.39 These findings by different teams suggest mucin in the medium might affect the expression of outer membrane protein and subsequently influence the function of A. muciniphila.