The production of antimicrobial compounds by British marine algae II. Seasonal variation in production of antibiotics

Eleven known antibiotic-producing species of British marine algae were quantitatively screened at monthly intervals for the presence of antibacterial compounds. The antibacterial components of the algae were extracted with acetone and then assayed against Staphylococcus aureus. The results indicate that seasonal variation in antibiotic production occurs in some marine algae and also that four main patterns of production can be discerned. These are, (a) the Polysiphonia type, in which antibiotic production occurs iniformly throughout the year; (b) the Laminaria type, which is characterised by maximum antibiotic production occurring during the winter months, this is also found in Chondrus crispus, Laurencia pinnatifida and Ulva lactuca; (c) the Dictyota type, possessing a summer peak of activity, which also occurs in Dilsea carnosa and Ascophyllum nodosum; (d) the Codium type, where there is a spring peak of activity, this is also exhibited by Halidrys siliquosa.