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Monoclonal Antibody to a Bacterial Endonuclear Symbiont Holospora Cross Reacts with Proteins of Contractile Vacuole Radial Canals of Paramecium Species
Author(s) -
DOHRA HIDEO,
FUJISHIMA MASAHIRO,
FOK AGNES K.,
ALLEN RICHARD D.
Publication year - 1994
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1994.tb06050.x
Subject(s) - macronucleus , paramecium caudatum , biology , immunoelectron microscopy , paramecium , antigen , monoclonal antibody , vacuole , cytoplasm , contractile vacuole , immunogold labelling , epitope , microbiology and biotechnology , antibody , paraformaldehyde , biochemistry , chemistry , immunology , gene , organic chemistry
A monoclonal antibody (mAb) IR‐2‐1 was raised against a 67‐kDa protein purified from the macronucleus‐specific bacterial symbiont Holospora obtusa of Paramecium caudatum. The mAb was found to react with two bands (31 and 67‐kDa) on gels of H. obtusa. Indirect immunofluorescence microscopy showed that these antigens were distributed inside the cells. However, unexpectedly, this mAb also cross reacted with the radial arms of the contractile vacuole in P. caudatum, P. tetraurelia, P. multimicronucleatum, P. jenningsi and P. bursaria as well as with their cytoplasm. Immunoelectron microscopy showed that the antigens were located on the decorated spongiome of the radial arms. In immunoblots, mAb IR‐2‐1 reacted with a band of 67 kDa in all Paramecium species examined. However, no band appeared in the immunoblot of isolated macronuclei of H. obtusa‐free P. caudatum and no label was seen in the nuclear matrix of the macronucleus of air‐dried P. caudatum. These results suggest that the 67‐kDa antigen found in H. obtusa was not imported from the host macronucleus and the same antigen in the host contractile vacuoles and cytoplasm were not derived from the symbiont. These results also showed that an epitope on the decorated spongiome of the Paramecium species is shared by its bacterial symbiont. In contrast to the decorated tubule‐specific mAb, DS‐1, the antigens for IR‐2‐1 appeared to be loosely membrane bound as they were lost in paraformaldehyde fixed and acetone permeabilized Paramecium. Supplementary key words. Contractile vacuole complexes, Holospora obtusa , monoclonal antibody, Paramecium.