Establishment of diatom endosymbiosis in Amphistegina lobifera
Chai, J. and Lee, J.J.
Dept. Biol., City College of CUNY and Graduate Center, Convent Ave, 138 St,
New York, NY 10031, USA
An antibody to a 104kDa glycopolypeptide found in all symbiotic diatoms of benthic foraminifera was shown to significantly interfere with host-symbiont recognition. Immunocytochemical study showed that this molecule was widely distributed in the symbiotic diatom cells when they were grown in culture. After internalization, newly ingested endosymbiotic diatoms were enclosed in symbiosomes as they were separated from their cell envelopes ( frustules ). The frustules were digested in separate vacuoles. Most of the newly taken up naked diatom protoplasts underwent a maturation process in which their cytoplasm was gradually lost. At maturity the protoplasts in symbiosomes had little cytoplasm with normal appearing chloroplasts and a nuclear remnant. The 104kDa protein was concentrated at the surface of the symbionts and their symbiosome membranes. Host lysosomes and other cytoplasmic vacuoles were not found in association with the signaling molecule. Evidence suggests that the symbiosomes do not fuse with lysosomes as phagosomes usually do.
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Wednesday, April 8 |
10:20 am |