C. Wiwat et al., INHIBITION OF A CONJUGATION-LIKE GENE-TRANSFER PROCESS IN BACILLUS-THURINGIENSIS SUBSP ISRAELENSIS BY THE ANTI-S-LAYER PROTEIN ANTIBODY, Current microbiology, 30(2), 1995, pp. 69-75
Extraction of the S-layer protein by treatment with 6 M urea revealed
a high-molecular-weight protein in the extracts obtained from Bacillus
thuringiensis subsp, israelensis (B.t.i.) strain 4Q2. This protein ba
nd was found to be absent in partially cured (4Q2-72) and completely c
ured (c4Q2-72) strains. The antibody toward this S-layer protein was p
repared and used to locate its antigenic protein on B.t.i cells by usi
ng indirect immunofluorescence. Immunodiffusion reactions and Western
blot analysis confirmed the specificity of the anti-S-layer protein an
tibody. It was found that the antibody against 4Q2 S-layer protein inh
ibited plasmid transfer via a conjugation-like process between B.t.i.
strains 4Q2-16 and c4Q2-72. That is, the frequency of transfer of plas
mid pBC16 was reduced from 9.7 x 10(-6) in the absence of the antibody
to less than 1.0 x 10(-8) in the presence of the antibody. The antibo
dy was also found to reduce the frequency of pBC16 plasmid transfer vi
a a conjugation-like process between B.t.i. strains A084-16-194 and c4
Q2-72 from 2.2 x 10(-5) in the absence of the antibody to 1.2 x 10(-6)
in the presence of the antibody.