Dinoflagellate Gonyaulax (Alexandrium) Tamarense and diatom Skeletonema costatum studies of extra-cellular ectocrinic and antimicrobial properties.

The two marine phytoplanktons, a dinoflagellate Gonyaulax (Alexandrium ) tamarense, and a diatom Skeletonema costatum, were used for analysis of the production of ectocrinic substances. The purpose of this study was to determine if there was any antimicrobial property found in the two marine organism's ectocrinic material. The two algal cultures were grown in an artificial sea water, (ASP8), and the algal ectocrinic isolates from this medium (ASP8) were analyzed. The Millipore separated liquid and solid extracts were purified for examination. The growth, collection and purification of the algae were performed by Dr. James E. Corrigan at a St. Francis College laboratory. The extracts were tested for any antimicrobial properties utilizing the Kirby-Bauer disc diffusion method on two types of medium, the Mueller Hinton agar (MHA), and the Tryptic Soy agar (TSA). Further testing was used to demonstrate whether amino acid and/or carbohydrate compounds were released by these organisms. The four areas where an antibiotic can produce inhibition are: cell wall synthesis, protein synthesis, cell membrane synthesis, and nucleic acid synthesis. The Kirby-Bauer disk diffusion method used the technique of impregnated standardized 6 mm diameter sized disks saturated with the known antibiotics onto a bacteria plated media. These plates were incubated for 36 hours, and any zones of inhibition observed around the disks were measured. The four types of bacteria used were: Streptococcus pyogenes, Bacillus subtilis, Neisseria sicca, and Escherichia coli. The four different bacteria were used to test the antimicrobial activity of the algal ectocrinic samples and to form a standard with the known antibiotics. The results of this investigation demonstrated that both marine organisms did produce minimal antimicrobial activity, and minimal carbohydrate and an amino acid compounds were detected.