Figure 5.

Expression of carotenoid hydroxylase and phytoene synthase genes in response to increased illumination. The H. pluvialis cells used for the preparation of RNA were harvested after 4 d of growth (lane 1) and after additional growth under high-light conditions for 12 (lane 2), 24 (lane 3), 48 (lane 4), and 72 (lane 5) h. For northern-blot analysis, the H. pluvialis carotenoid hydroxylase (A) and phytoene synthase (B) were used as specific probes. For comparison, total RNA was stained with ethidium bromide (C). In addition, the accumulation of astaxanthin was examined (D).