Ethanolamine Utilization in Bacteria.

Ethanolamine (EA) is a valuable source of carbon and/or nitrogen for bacteria capable of its catabolism. Because it is derived from the membrane phospholipid phosphatidylethanolamine, it is particularly prevalent in the gastrointestinal tract, which is membrane rich due to turnover of the intestinal epithelium and the resident microbiota. Intriguingly, many gut pathogens carry the (ethanolamine utilization) genes. EA utilization has been studied for about 50 years, with most of the early work occurring in just a couple of species of Once the metabolic pathways and enzymes were characterized by biochemical approaches, genetic screens were used to map the various activities to the genes. With the rise of genomics, the diversity of bacteria containing the genes and surprising differences in gene content were recognized. Some species contain nearly 20 genes and encode many accessory proteins, while others contain only the core catabolic enzyme. Moreover, the genes are regulated by very different mechanisms, depending on the organism and the regulator encoded. In the last several years, exciting progress has been made in elucidating the complex regulatory mechanisms that govern gene expression. Furthermore, a new appreciation for how EA contributes to infection and colonization in the host is emerging. In addition to providing an overview of EA-related biology, this minireview will give special attention to these recent advances.