Ga. Dykes et Jw. Hastings, SELECTION AND FITNESS IN BACTERIOCIN-PRODUCING BACTERIA, Proceedings - Royal Society. Biological Sciences, 264(1382), 1997, pp. 683-687
Bacteriocins are proteinaceous anticompetitor molecules produced by ba
cteria against closely related species. A number of theoretical models
have been used to explain experimental data that indicate high polymo
rphisms among bacteriocins and a frequency-dependent nature of selecti
on for bacteriocin-producing strains. The majority of these experiment
al data were, however, obtained from investigations into the colicin g
roup of bacteriocins produced by Gram-negative bacteria. The conclusio
ns drawn from these models have been extrapolated to other bacteriocin
s and allelopathic compounds in general. Examination of more recent ex
perimental investigations into the bacteriocins of Gram-positive bacte
ria indicate a lower degree of polymorphism and a less frequency-depen
dent mode of selection among these strains than among the colicin-prod
ucing strains. Here we examine these contradictions in the light of th
e assumptions and conclusions of the theoretical models and reported d
ata. We show that fitness costs (as indicated by decreased relative ma
ximum growth rate) associated with bacteriocin production may be much
lower in many cases than is assumed in the present models. A lower fit
ness cost associated with bacteriocin production adequately explains t
he newer data from Gram-positive bacteria cited here, and indicates th
at extrapolation of existing models to all bacteriocins and other alle
lopathic compounds is not appropriate.