Abstract
Endotoxic glycolipids (ReGl) extracted from the whole cells (WC) and cell walls of heptose-less Re mutant of Salmonella minnesota with hot phenol-water (PW), phenol-chloroform-petroleum ether (PCP), and chloroform-methanol (CM) were analyzed chemically and examined with an electron microscope. ReGl-PW-(WC) contained mannose and proteins as contaminants, ReGl-PCP(WC) consisted of an excess amount of amino compound (cadaverine), and ReGl-CM(WC) consisted of proteins and cadaverine, in addition to the ReGl constituents.
The ultrastructure of ReGl-PW(WC) resembled onions when stained with uranyl formate, and was spherical when stained with uranyl acetate, sodium phosphotungstate and ammonium molybdate, whereas those of ReGl-PCP(WC) and ReGl-CM(WC) were shaped like ribbons. However, the shadowed ultrastructures of ReGl-PCP(WC) and ReGl-CM(WC) showed small pieces of flat and wide sheets, respectively. ReGl-PCP(WC) re-extracted by the PW method was found to be converted into the onion-like structure which was similar to that of ReGl-PW(WC), while an intermediate form (fingerprint-like) was observed after re-extraction of ReGl-PW(WC) with PCP. It was strongly suggested that the ultrastructural arrangement of ReGl was dependent on the solvent systems used for extraction.
