In preliminary studies we have found that several pathogens, namely menigococci, E. coli, and the gonococcus produce substantial amounts of polyphosphate (PP). In the case of the two neisserial species nearly half of the PP can be washed off the surfac eof the organism with neutral buffer. Examination of viability and release of cytoplasmic enzymes indicates that his "external PP" is not a result of autolysis. The elemental analysis of purified gonococcal PP indicated that it consists of sodium phosphate and a small amount of carbon. The carbon was identified to be a diacylglyceral group attached to the PP containing mainly palmitic an dsteric acid. In this regard the material resembles the capsular polysaccharides of the meningococcus and of virulent E. coli. While the presence of PP in microorganism has been recognized for 90 years this substance has not been implicated in pathogenesis. Since we find that at least two common pathogens synthesize large amounts of external PP we propose to examine its role in pathogenesis. To accomplish this we will develop genetic methods to obtain gonococcal mutants unable to produce PP and compare them to their parents in model systems. These include complement action, phagocytosis, iron uptake, and virulence in chick embryos.