Biology subjects

Townsend, G. E.

Publications and source records attributed to Townsend, G. E..

3 recordsLinked to original sources

bioRxiv2026

A conserved peptidase governs glucose homeostasis in Bacteroides

Glucose homeostasis is governed by peptidases across the kingdom of life. Host overconsumption of glucose transforms gut microbial compositions and activities. Here, we identify an IDE-like M16 peptidase in human gut commensal Bacteroides that controls glucose-dependent inhibition of the transcriptional regulator, Cur, which is important for intestinal colonization and host-microbial interactions. This regulatory paradigm is independent of fructose, establishing a specific pathway whereby glucose signaling hinders commensal fitness in the host. We determined that this peptidase cleaves targets of other M16-family peptidases, including insulin, to control carbon metabolism through the oxidative pentose phosphate pathway (OPPP). Furthermore, we show that peptidase activity governs the abundance of glycolytic enzymes to alter Cur activity. These findings establish that the activity of an M16 peptidase mediates changes to global transcription in Bacteroides species when glucose is abundant in the host diet.

microbiology↗

bioRxiv2025

A high-throughput microbial glycomics platform for prebiotic development

The mammalian intestine contains diverse carbohydrate pools that govern the gut microbiome composition. Structurally distinct polysaccharides, also called glycans, are differentially consumed by gut microbial subsets and direct their abundance by controlling gene expression and metabolite production. Therefore, identifying gut microbial accessible carbohydrates (MACs) is necessary to develop new prebiotics that beneficially manipulate the gut microbiome. However, no methods exist to efficiently examine MACs in biologically-derived mixtures. Here, we present a high-throughput platform to detect MACs from various plant, animal, and microbial sources using a genome-wide library of engineered Bacteroides thetaiotaomicron (Bt) strains that harness their endogenous glycan detection machinery. We demonstrate that this platform exhibits specific and sensitive responses to glycan mixtures and use bacterially-encoded proteins to characterize a previously unknown MAC from yeast. Expanding this technology across gut Bacteroides species will generate a broadly applicable approach to characterize heterogeneous glycan mixtures and identify prebiotic substrates.

molecular biology↗

bioRxiv2024

Hierarchical glycolytic pathways control the carbohydrate utilization regulator in human gut Bacteroides

Human dietary choices control the gut microbiome. Industrialized populations consume abundant amounts of glucose and fructose, resulting in microbe-dependent intestinal disorders. Simple sugars inhibit the carbohydrate utilization regulator (Cur), a transcription factor in members of the prominent gut bacterial phylum, Bacteroidetes. Cur controls products necessary for carbohydrate utilization, host immunomodulation, and intestinal colonization. Here, we demonstrate how simple sugars decrease Cur activity in the mammalian gut. Our findings in two Bacteroides species show that ATP-dependent fructose-1,6-bisphosphate (FBP) synthesis is necessary for glucose or fructose to inhibit Cur, but dispensable for growth because of an essential pyrophosphate (PPi)-dependent enzyme. Furthermore, we show that ATP-dependent FBP synthesis is required to regulate Cur in the gut but does not contribute to fitness when cur is absent, indicating PPi is sufficient to drive glycolysis in these bacteria. Our findings reveal how sugar-rich diets inhibit Cur, thereby disrupting Bacteroides fitness and diminishing products that are beneficial to the host.

microbiology↗