- March 17, 2023Source: YaleNews
Boosting Survival of a Beneficial Bacterium in the Human Gut
- January 09, 2023
Postdoctoral position available in the Groisman lab, Microbial Sciences Institute at Yale University
- August 10, 2022
Dr. Weiwei Han presents Ph.D. thesis
- April 29, 2022Source: YaleNews
Eight Yale Faculty Members Elected to American Academy of Arts and Sciences
- September 20, 2019
Groisman receives mentorship award
- December 16, 2018
Sugar targets gut microbe linked to lean and healthy people
- June 22, 2018
Nine Faculty Members Appointed to Endowed Positions
- October 13, 2016
In creation of cellular protein factories, less is sometimes more
- October 13, 2016
In creation of cellular protein factories, less is sometimes more
Welcome
The Groisman Lab seeks answers to a fundamental biological question: How does an organism know when, where, and for how long to turn a gene on or off?
We address this question by investigating bacterial species that establish intimate interactions with animal hosts.
Research
Bacteria require phase separation for fitness in the mammalian gut
RNA-seq analysis was performed in cecal contents of ex−germ-free mice (C57BL/6 mice, n = 5) monocolonized with strains harboring WT Rho (AK310) or ΔIDR (AK312) Rho. (A) Volcano plot of gene RNA abundance in the WT versus ΔIDR Rho strains as log2-fold change versus -log(p). Genes >2-fold up-regulated (blue) or down-regulated (orange) in the ΔIDR background are highlighted. (FDR-adjusted P value <0.05). (B) Heat map of genes differentially expressed in strains harboring WT Rho versus ΔIDR Rho based on molecular function. (C) KEGG pathway enrichment analysis of differentially expressed in strains harboring WT Rho versus ΔIDR Rho. Identified pathways with enrichment p-value <0.05 and number of genes per pathway shown. (D) Log2 fold change of genes identified in (C).
Gut colonization by Bacteroides requires translation by an EF-G paralog lacking GTPase activity.
Gut-commensal Bacteroides thetaiotaomicron harbors a second paralog of translation elongation factor EF-G, EF-G2. Here, EF-G2 is found to increase bacterial fitness in the nutrient-fluctuating gut environment by mediating slow translation without GTP hydrolysis.
H-NS degradation is necessary for gut colonization by E. coli.
Differential synthesis of novel small protein times Salmonella virulence program.
Two different mRNAs from the ugtSugtL bicistron time the S. Typhimurium PhoP virulence program inside macrophages.
We report that persistent bacteria form as a result of slow growth alone, despite opposite changes in the abundance of proteins, metabolites, and signaling molecules. Our findings argue that transitory disturbances to core activities, which are often linked to cell growth, promote a persister state regardless of the underlying physiological process responsible for the change in growth.
The bacterium Salmonella enterica serovar Typhimurium narrows down the spectrum of substrates degraded by the proteases Lon and ClpAP in response to low cytoplasmic Mg2+, a condition that decreases protein synthesis. This control is exerted by PhoP, a transcriptional regulator activated in low cytoplasmic Mg2+ that governs proteostasis and is conserved in enteric bacteria. The uncovered mechanism enables bacteria to control the abundance of preexisting proteins.
Illustrated by Jennifer Aronson
The Expanded Specificity and Physiological Role of a Widespread N-degron Recognin.
Candidate ClpS substrates revealed by proteomics.
The small proteins MgtU and MgtR regulate Salmonella virulence and growth in low Mg2+ conditions by controlling the stability of the Mg2+ transporters MgtA and MgtB.
FEDS: a Novel Fluorescence-Based High-Throughput Method for Measuring DNA Supercoiling In Vivo.
Map of SupR, a supercoiling reporter plasmid for enterobacteria.
Dietary sugar silences a colonization factor in a mammalian gut symbiont.
Dietary components are believed to influence the composition of the gut microbiota by serving as nutrients to a subset of microbes, thereby favoring their expansion. However, we now report that dietary fructose and glucose, which are prevalent in the Western diet, specifically silence a protein that is necessary for gut colonization, but not for utilization of these sugars, by the human gut commensal Bacteroides thetaiotaomicron. Our findings underscore a role for dietary sugars that escape absorption by the host intestine and reach the microbiota: regulation of gut colonization by beneficial microbes independently of supplying nutrients to the microbiota.
Metabolic flux controls chondroitin sulfate utilization in Bacteroides thetaiotaomicron.