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RECOMMENDATIONS FOR QUICK IDENTIFICATION
OF LUMINOUS BACTERIA
Among the luminous bacteria isolated from various natural
sources, the most frequently found are the following: Photobacterium phosphoreum, Photobacterium leiognathi, Vibrio fischeri
and Vibrio harveyi.
Due to their ability to emit visible light luminous
bacteria colonies on solid medium can be easily differentiated from other
bacterial colonies in darkness. Bacteria V.
fischeri form yellow pigment and can be easily differentiated by the colony
colour. V.harveyi produce into the medium brown pigment, their colonies have
respective colouring in case of long cultivation or storage on solid medium.
The genus of luminous bacteria can be determined by
examining the form of growth in semi-liquid agar (compact, usually consisting
of microcolonies - for Photobacterium;
dissipated, homogeneous - for Vibrio)
[Medvedeva et al., 1993], and by estimating the luminescence reaction kinetics
[Vorobyova et al., 1982, Sandalova, Tyulkova, 1992]. The specific dependence of
the luminescence reaction kinetics on the length of the aldehyde used makes it
possible to assign luminous bacteria to certain species [Vorobyova et al.,
1982].
Taxonomically close species, P.phosphoreum and P.leiognathi,
have different temperature characteristics of growth. P.phosphoreum strains
grow at 4oC, however most of them terminate their growth at a
temperature of 25oC and have optimal temperatures of growth between
18 and 20oC. P.leiognathi
strains grow well at temperatures between 30 and 35oC, don't grow at
4oC and above 40oC.
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