The physiology and biochemistry of zooxanthellae symbiotic with marine coelenterates III. The effect of homogenates of host tissues on the excretion of photosynthetic products in vitro by zooxanthellae from two marine coelenterates

Abstract

When freshly isolated zooxanthellae from Anthopleura elegantissima were incubated in NaH$^{14}$CO$_{3}$ in the light in a homogenate of tissues of their animal hosts they excreted much more organic $^{14}$C than when incubated in sea water only. The homogenate of aposymbiotic (algae-free) animals could enhance excretion by the algae only after the animals had become infected with zooxanthellae. On prolonged isolation, zooxanthellae from A. elegantissima and Zoanthus pacifica excrete progressively less of the $^{14}$C fixed in photosynthesis. Return of algae from A. elegantissima after extended isolation to host homogenate causes the release of similar amounts of $^{14}$C as freshly isolated algae, but with marked qualitative and quantitative differences in the distribution of $^{14}$C.