Bacteria in the gastrointestinal tract (GI) produce a variety of amino acid bile acid amidates that impact host-mediated metabolic processes; however, the bacterial gene(s) responsible for their production remain unknown. Herein, we report that bile salt hydrolase (BSH) possesses dual functions, including a new role in bile acid metabolism by functioning as an amine N-acyl transferase that conjugates amines to form bacterial bile acid amidates (BBAAs). To characterize this new amine N-acyl transferase role for BSH, we used pharmacological inhibition of BSH, heterologous expression of bsh in Escherichia coli, and generated a bsh knockout and knockin in Bacteroides fragilis to demonstrate that BSH is necessary and sufficient for BBAA production. Lastly, we report that BBAAs activate host ligand-activated transcription factors including the farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, and the aryl hydrocarbon receptor. These new findings expand our understanding and appreciation for the important roles that bacteria play in shaping the bile acid metabolic network.

Background University and college students are vulnerable to developing depressive symptoms. People in low-income countries are disproportionately impacted by mental health problems, yet few studies examine routes to accessing clinical services. Examining motivation and barriers toward seeking clinical mental health services in university students in Bangladesh is important. Method Using a cross-sectional survey (n = 350), we assess the relationship between the constructs of autonomy, relatedness, and competency toward using clinical mental health practices (i.e. using professional resources, taking medication) with (1) positive views, (2) perceived need, and (3) use of clinical mental health services among Bangladeshi university students. Results Results showed that the perceived need for mental health support was the predictor of the largest magnitude (aOR = 4.99, p = 0.005) for using clinical services. Having a positive view of clinical services was predictive of clinical service use (aOR = 2.87, p = 0.033); however, that association became insignificant (p = 0.054) when adjusting for the perceived need for mental health care. Of the SDT constructs, social influences were predictive of perceiving a need for mental health support, and mental health knowledge was predictive (aOR = 1.10, p = 0.001) of having a positive view of clinical mental health care. Conclusion Our findings show that knowledge of mental health is associated with positive views of mental health services, and that higher levels of stress and the presence of people with mental health problems are associated with the perception of a need for mental health care, which is ultimately responsible for using the services.

Two-component extracellular copper sensing from the periplasm of Gram-negative bacteria has been well studied, but copper detection at the cell surface of the Gram-positive L. monocytogenes is less understood. Collectively, our results show that EET is most active under anaerobic conditions and reduces Cu 2+ and Ag 1+ to, respectively, generate or remove the monovalent ligands that directly bind to CopS and lead to the induction of lipoprotein remodeling genes.