Satoka Aoyagi oral presentation (OB3-Wed2-1-2)
Evaluation of Paramecium bursaria with symbiotic Chlorella variabilis using TOF-SIMS with Ar cluster ion beam
1 Seikei University, 3-3-1 Kichijoji-kitamachi, 1808633 Musashino, Tokyo, Japan
2 Shaman University, 1060 Nishikawatsu-cho, 6908504 Matsue, Shimane, Japan
3 Corporate Engineering Division, Appliances Company - Panasonic Corporation, 3-4 Hikaridai, Seika-cho, Sourakugunn, 619-0237 Kyoto, Japan
Symbiotic relationship between Paramecium bursaria (P. bursaria) and symbiotic algae, Chlorella variabilis (C. variabilis), was investigated based on the evaluation of perialgal vacuole (PV) membrane of P. bursaria surrounding Chlorella by means of time-of-flight secondary ion mass spectrometry (TOF-SIMS). The association of P. bursaria with symbiotic C. variabilis is a mutual symbiosis . For instance, algae-bearing P. bursaria can grow better than non-algae-bearing cells because the alga has a photoprotective role for the host. Timing of cell divisions of both the algae and the host cells is well coordinated. In order to clarify detailed mechanisms of their symbiotic systems, it is necessary to identify PV membrane although any ingredients of PV membrane have not been revealed yet due to its fragile structure.
Since TOF-SIMS with a gas cluster ion beam (GCIB) such as an Ar cluster ion beam enables 3D analysis of biotissues and cells, P. bursaria with symbiotic Chlorella samples (the optic image of a typical sample is shown in Fig. 1) were measured using TOF-SIMS with Ar cluster ion beam sputtering. The TOF-SIMS results of P. bursaria with symbiotic Chlorella samples were compared with those of P. bursaria without Chlorella, which has digestive vacuole (DV) membrane, to clarify main ingredients specific to PV membrane.
As a result, secondary ions specific to P. bursaria with symbiotic Chlorella samples were found. Since their distribution is slightly different from that of phosphocholine related fragment ions such as m/z 184.1 and 86.1, it is suggested that the structure of PV might be different from general biomembranes.
 Y. Kodama and M. Fujishima “Infection of Paramecium bursaria by Symbiotic Chlorella Species” from “Endosymbionts in Paramecium, Ed. By M. Fujishima”, Springer (2009).