LOCALIZATION OF THE DIVISION PROTEIN FTSZ IN MYCOPLASMA CELLS MYCOPLASMA HOMINIS
I. E. Vishnyakov,1 S. N. Borchsenius,1,* Yu. I. Basovskii,2 S. A. Levitskii,2
V. N. Lazarev,2 E. S. Snigirevskaya,1 Ya. Yu. Komissarchik 1
1 Institute of Cytology RAS, St. Petersburg, and 2 Institute of Physical-Chemical Medicine, Federal Agency of Public
Health and Social Development, Moscow;
* e-mail: borch@mail.cytspb.rssi.ru
Localization of the protein FtsZ in Mycoplasma hominis cells was determined. Ultra thin sections were treated by rabbit polyclonal antibodies against
FtsZ Ì. hominis: a conjugate of protein A with colloidal gold particles was used instead of secondary antibodies. Considerable polymorphism of cells was
seen on electron micros copy pictures of Ì. hominis cells, which is typical for mycoplasmas. Among a wide variety of cell shapes we distinguished
dumbbell-shaped dividing cells, and the cells connected with each other with the aid of thin membrane tubules (former constrictions). Dominants distribution of
the label in the constriction area of dividing Ì. hominis cells and in the area of the thin membrane tubules was observed. We revealed the cross septum
in the mycoplasma cells for the first time, as well as the gold labeling of this structure. Furthermore, in some rounded and oval cells colloidal gold particles labeled
the whole plasma membrane in ring-shaped manner. Probably, the label in these cases marks a submembrane contractile ring (Z-ring). The facts mentioned above
confirm that FtsZ of Ì. hominis plays an active role in the mycoplasma cytokinesis. In a series of cases spiral-like distribution of gold particles was observed.
Probably, FtsZ protofilaments in Ì. hominis cells can form spiral structures similar to Z-spirals of Bacillus subtilis and Escherichia coli.
Its presence in mycoplasma cells may be considered as an important argument in favour of model of Z-ring assembling through reorganization of Z-spirals. FtsZ also
may participate in maintenance of mycoplasma cell shape (membrane localization).
Key words: FtsZ, mycoplasmas, M. hominis, immunocytochemisty, Z-ring, Z-spiral
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