Growth induction and stabilization of population composition in Saccharopolyspora erythraea by catecholamine compounds

Dopamine and epinephrine, hormone compounds belonging to the catecholamine group, produced a polymodal effect on the culture of the erythromycin-producing actinobacterium Saccharopolyspora erythraea. They stimulated spore germination and stabilized the composition of its population. Plating of monospore suspensions of strains RIA 1387 and RIA 120 in the presence of catecholamines increased the colony number by 2- and 2.3-fold, respectively (with epinephrine), and 3- and 4-fold, respectively (with dopamine). The optimum effect of both catecholamines was attained at a concentration of 10(-5) M. The influence of exogenous catecholamines resulted in a significant shift in the population structure of the tested strains with an increased share of the colonies of the dominant morphotype, which is the most efficient antibiotic producer. Considerable differences in the biological activity of the catecholamines were revealed after exposure to ultralow temperatures both during medium-term storage (for three months) and after short-term freezing (for 10 min) in liquid nitrogen. An appreciable effect was produced by exogenous dopamine introduced at the resuscitation stage, resulting in a two- to three-fold increase in the viability of actinobacterial spores. Almost 100% of the resulting populations were composed of colonies of the dominant morphotype. In contrast to dopamine, epinephrine failed to produce a growth-stimulating effect when added to spore suspensions exposed to ultralow temperatures.