A Bacterial Microcompartment Is Used for Choline Fermentation by Escherichia coli 536

Abstract

Bacterial choline degradation in the human gut has been associated with cancer and heart disease. In addition, recent studies found that a bacterial microcompartment is involved in choline utilization by and species. However, many aspects of this process have not been fully defined. Here, we investigate choline degradation by the uropathogen 536. Growth studies indicated 536 degrades choline primarily by fermentation. Electron microscopy indicated that a bacterial microcompartment was used for this process. Bioinformatic analyses suggested that the choline utilization () gene cluster of 536 includes two operons, one containing three genes and a main operon of 13 genes. Regulatory studies indicate that the gene encodes a positive transcriptional regulator required for induction of the main operon in response to choline supplementation. Each of the 16 genes in the cluster was individually deleted, and phenotypes were examined. The ,, ,, ,, , and genes were required for choline degradation, but the remaining genes of the cluster were not essential under the conditions used. The reasons for these varied phenotypes are discussed. Here, we investigate choline degradation in 536. These studies provide a basis for understanding a new type of bacterial microcompartment and may provide deeper insight into the link between choline degradation in the human gut and cancer and heart disease. These are also the first studies of choline degradation in 536, an organism for which sophisticated genetic analysis methods are available. In addition, the gene cluster of 536 is located in pathogenicity island II (PAI-II) and hence might contribute to pathogenesis.

Glycyl Radical Enzyme-Associated Microcompartments: Redox-Replete Bacterial Organelles

“…These studies provided the first biochemical evidence linking choline degradation to bacteria containing GRM2 loci and have been further validated by knockout and complementation studies of the specific GRM2 GREs from Proteus mirabilis DSM4479 (35) and E. coli 536 (36).…”

Metformin decreases bacterial trimethylamine production and trimethylamine N-oxide levels in db/db mice

“…The effect of metformin on TMA synthesis also appears to be rather complex. Choline degradation to TMA in bacteria occurs in specialized microcompartments that contain choline-TMA-lyase 39 . Our data imply that other components or processes like co-factor recycling in these microcompartments but not choline-TMA-lyase itself are affected by metformin resulting in overall inhibition of TMA production.…”

Biological oxidation of choline‐based ionic liquids in sequencing batch reactors

“…As can be seen in Fig. , the first step of the degradation process is the formation of various amines (tri‐, di‐ and methylamine) and ethanol, which is consistent with previous reports . Then, the microbial community efficiently degrades these compounds to CO 2 , H 2 O, nitrite and nitrate as end‐products.…”

“…5, the first step of the degradation process is the formation of various amines (tri-, di-and methylamine) and ethanol, which is consistent with previous reports. 34,74,75 Then, the microbial community efficiently degrades these compounds to CO 2 , H 2 O, nitrite and nitrate as end-products. Intermediates from glucose degradation including xylulose, acetylphosphate and ethanol also were detected in the medium.…”