CHANGES IN CHEMICAL-COMPONENTS AND ENERGY-CHARGE DURING GROWTH-CYCLE OF CHATTONELLA-ANTIQUA

The changes in cellular content of adenosine triphosphate (ATP) in Chattonella antiqua (Hada) Ono (Raphidophyceae), a red tide microorganism, were determined during growth in laboratory culture using ESM-enriched seawater. Carbon, nitrogen, and phosphorus in the cells were also analyzed. The cellular content of ATP decreased within several hours Of inoculation into fresh medium, then rapidly increased during the early exponential Phase of growth to 20-30 pg ATP cell-1. After the mid exponential phase ATP decreased and reached a constant level from the late exponential phase to the stationary phase at 5-10 Pg ATP cell-1. The decrease of ATP after inoculation seemed to be due to a lack of extracellular organic materials in the fresh medium. The addition of both low and high molecular fractions obtainned by dialysis from early stationary phase cultures of C. antiqua increased the cellular ATP content in the early exponential phase. The energy charge decreased from 0.63 to about 0.5 during the lag phase and recovered during the exponential phase. The lag phase in C. antiqua culture is the period of adaptation to fresh medium possibly by the production of extracellular organic materials at the expense of cellular ATP.