Biology subjects

Brislawn, C. J.

Publications and source records attributed to Brislawn, C. J..

2 recordsLinked to original sources

bioRxiv2018

Lactobacillus acidophilus disrupts collaborative multispecies bile acid metabolism

Bile acids are metabolic links between hosts and their gut microbiomes, yet little is known about the roles they play in microbe-to-microbe interactions. Here we present a study designed to investigate the effect that a common probiotic, Lactobacillus acidophilus, has on microbial interactions that lead to formation of secondary bile acids. A model microbial consortium was built from three human gut isolates, Clostridium scindens, Collinsella aerofaciens, and Blautia obeum, and cultured under different bile acid and probiotic treatments. A multi-omics platform that included mass spectrometry-based metabolomics and activity-based proteomic probes was used to produce two major results. The first, was that an uncommon secondary bile acid - ursocholate - was produced by a multi-species chemical synthesis pathway. This result highlights a new microbe-to-microbe interaction mediated by bile acids. The second finding was that the probiotic strain, L. acidophilus, quenched the observed interactions and effectively halted consortial synthesis of ursocholate. Little is known about the role that ursocholate plays in human health and development. However, we did discover that a decrease in ursocholate abundance corresponded with successful weight loss in patients after gastric bypass surgery versus those who did not lose weight after surgery. Hence, this study uncovered basic knowledge that may aid future designs of custom probiotic therapies to combat obesity.

microbiology↗

bioRxiv2018

Forfeiting the founder effect: turnover defines biofilm community succession

Microbial community succession is a fundamental process that effects underlying functions of almost all ecosystems; yet the roles and fates of the most abundant colonizers are poorly understood. Does early abundance spur long term persistence? How do deterministic and stochastic processes influence the roles of founder species? We performed a succession experiment within a hypersaline microbial mat ecosystem to investigate how ecological processes contributed to the turnover of founder species. Bacterial and micro-eukaryotic founder species were identified from primary succession and tracked through a defined maturation period using 16S and 18S rRNA gene amplicon sequencing in combination with high resolution imaging that utilized stable isotope tracers to evaluate basic functional capabilities. The majority of the founder species did not maintain high relative abundances in later stages of succession. Turnover (versus nestedness) was the dominant process shaping the final community structure. We also asked if different ecological processes acted on bacteria versus eukaryotes during successional stages and found that deterministic and stochastic forces corresponded more with eukaryote and bacterial colonization, respectively. Our results show that taxa from different kingdoms, that share habitat in the tight spatial confines of a biofilm, were influenced by different ecological forces and time scales of succession.

ecology↗