The cyl genes of Streptococcus agalactiae are involved in the production of pigment

The cyl genes of Streptococcus agalactiae are required for the production o f hemolysin. Based on the observation that nonhemolytic S. agalactiae mutan ts do not produce pigment, a close genetic linkage between hemolysin and pi gment has been postulated. To investigate this genetic linkage and to ident ify genes involved in the production of the S. agalactiae pigment, we scree ned mutant libraries for nonpigmented clones. Four distinct mutants were is olated with a nonpigmented and nonhemolytic phenotype. The mutations had oc curred either in known cyl genes or in two open reading frames located imme diately downstream. These novel genes are cotranscribed with the cyl gene c luster and were designated cylF and cylI. Our data indicate that identical genes participate in the production of S. agalactiae hemolysin and pigment. (C) 2000 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.