Bunin V.D., Ignatov O.V., Guliy O.I., Zaitseva I.S.,
O'Neil D., Ivnitski D. |
|
Abstract
This article describes electrooptical (EO) characterization of biospeciWc binding between the
bacterium Escherichia coli XL-1 and the phage M13K07. The electrooptical analyzer (ELUS EO), which
has been developed at the State Research Center for Applied Microbiology, Obolensk, Russia, was
used as the basic instrument for EO measurements. The operating principle of the analyzer is
based on the polarizability of microorganisms, which depends strongly on their composition,
morphology, and phenotype. The principle of analysis of the interaction of E. coli with the phage
M13K07 is based on registration of changes of optical parameters of bacterial suspensions. The
phage–cell interaction includes the following stages: phage adsorption on the cell surface, entry
of viral DNA into the bacterial cell, ampliWcation of phage within infected host, and phage
ejection from the cell. In this work, we used M13K07, a Wlamentous phage of the family Inoviridae.
Preliminary study had shown that combination of the EO approach with a phage as a recognition
element has an excellent potential for mediator-less detection of phage–bacteria complex formation.
The interaction of E. coli with phage M13K07 induces a strong and speciWc EO signal as a result
of substantial changes of the EO properties of the E. coli XL-1 suspension infected by the phage
M13K07. The signal was speciWc in the presence of foreign microXora (E. coli K-12 and Azospirillum
brasilense Sp7). Integration of the EO approach with a phage has the following advantages: (1)
bacteria from biological samples need not be puriWed, (2) the infection of phage to bacteria is
speciWc, (3) exogenous substrates and mediators are not required for detection, and (4) it is
suitable for any phage–bacterium system when bacteria-speciWc phages are available. |
