FIG. 2.

Effects of light on proliferation of Pfiesteria spp. on algal prey. (A) Proliferation of P. piscicida and depletion of Rhodomonas with and without light. Cell densities of P. piscicida (○) and Rhodomonas (□) exposed to 14 h of light/10 h of darkness (left panel) and 24 h of darkness (right panel) were determined by counting (error bars, standard deviations; n, 3 replicate experiments). Dashed lines indicate the highest cell density of P. piscicida with light cycle. (B) Detection of Rhodomonas in culture by a specific PCR assay for Rhodomonas actin and chloroplastic GAPDH DNA. Samples were collected every day for the extraction of RNA and the synthesis of cDNA.