This product is an extract of E. coli B (ATCC 11303) grown in Kornberg Minimal media at 37°C and taken at 3/4 log growth phase. Total E. coli lipid extract is a chloroform:methanol extract of the respective tissue. This extract is partitioned against deionized water and the chloroform phase is concentrated. Polar lipid extract is the total lipid extract precipitated with acetone and then extracted with diethyl ether.