POSTERS - BLAST X - University of Utah

BLAST X Poster #45
TETHERED MYCOPLASMA
Daisuke Nakane and Makoto Miyata
Department of Biology, Graduate School of Science, Osaka City University
Mycoplasma mobile is a pathogenic flask-shaped bacterium 0.8 micron long. They bind
to solid surfaces by “legs” sticking out from the base of membrane protrusion, “neck”, and glide
by a unique mechanism. Recently, we proposed a working model, power stroke model, where
the cells are propelled by many legs repeatedly catching and releasing the solid surface, driven
by the energy of ATP hydrolysis. Here, to detect the movement of legs, we reduced the number
of working legs and amplified the leg movement.
When the cells were treated by 0.1% Tween 60, they were elongated from 0.8 micron to
2.0-4.0 micron in 15 min with the extension of cytoskeletal structures. A previous study showed
that the direct binding target of mycoplasma is a sialic acid, and the addition of free sialic acids
dissociated gliding cells from the solid surface. Here, in the presence of 0.25-1 mM of sialic
acid, the elongated cells pivoted widely, plausibly resulting from the reduction the leg number.
The pivoting ceased when strong light was applied in the presence of a fluorescence dye,
suggesting that the pivoting is caused by the gliding legs. Azide and the antibody against the
gliding machinery affected the distribution of pivoting angle differently, although both reduce the
gliding speed. On the basis of these results, the movements of legs will be discussed.
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