Sex pheromones and plasmid transfer in Streptococcus faecalis: a pheromone, cAM373, which is also excreted by Staphylococcus aureus.

Within a highly evolved mult icel lular organi sm, communicat ion between dis tally located ce l l s occurs by means o f a variety o f different chemica l s ignals . These hormonal substances play important roles in deve lopment , maintenance, and fertility and are a lso involved in coordinating immune and neurological responses to external st imuli . Chemical communicat ion can also occur between individual organisms , and the m o l e c u l e s representing these s ignals are referred to as pheromones (Karlson and Luscher 1959) . Wellknown examples o f pheromones in higher sys tems include those serving as sex attractants in insects and certain vertebrates. Communicat ion between unicellular organisms is , by def ini t ion, via phero m o n e s , and the involvement o f such substances in certain stages o f devel opment is wel l known or has been implicated in a number o f microbial spec ies (Ensign 1978; Hirosawa and Wolk 1979; Kaiser et al. 1979; Biro et al . 1980; Aaronson 1981; Stephens et al. 1982). Chemical substances that are excreted and facilitate mating between t w o organisms are cal led sex pherom o n e s ; these compounds and their behavior have been studied in fungi , algae (Kochert 1978), and ci l iates (Nanney 1977). Much attention has been focused on the yeast a and a-factors and the mating phenomena associated with their