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Computation coefficients for estimating the effectiveness of bioluminescence expression in natural luminescent bacteria P. leiognathi 54 and transgenic strain E. coli Z905/pPHL7 bearing lux-operon in multicopy plasmid are suggested, and their use on the molecular, cell, and population levels was considered. It was shown that, on the population level, all transgenic variants got the better of natural variants of P. leiognathi 54 irrespective of the type of lux-operon regulation. On the cell level, in the bright and dim variants of the transgenic strain, the effectiveness of bioluminescence expression increases by several orders. On the level of one lux-operon, the effectiveness of expression of the bright variant of transgenic strain is substantially higher than in the natural bright variant; in dim variants, the efficiency values are similar, and the effectiveness of bioluminescence expression in the dark variant of E. coli Z905-2 /pPHL7 is by two orders lower than that in the dark variant of P. leiognathi 54.

Manifestation of pleiotropic effects in the isogenic variants of luminescent bacteria Photobacterium leiognathi 54 was investigated. The decrease or increase of the expression level of bioluminescence was caused by changes in lux operon regulation. The dynamics of the bioluminescence of dark and dim variants did not differ from the dynamics of the initial luminescent variant, but dependence of the level of luminescence intensity on the exogenous autoinductor of the lux operon was revealed. The investigated variants of P. leiognathi 54 inherited fairly stable morphological characteristics, colony architectonics, level of luminescence, and activity of some enzymes; variants with reduced bioluminescence formed colonies of the S type. Stable bright variants with S- and R-type colonies appeared both in the initial strain population and in the dark variant population, but with smaller frequency. Populations of the bright variant with R-type colonies were most heterogeneous; this can be determined by the lack of glucose repression of the bioluminescence in contrast to other investigated variants of P. leiognathi.

The influence of some chemical substances on luminous bacteria was studied to elucidate the interrelation between the xenobiotics action on bacterial luminescence and cell ultrastructure. Such substances as quinones, phenols, chlorides of heavy metals (in concentrations of substances inhibiting luminescence by 50%) resulted in damaging effects upon bacteria: a lot of cells had damage of membranes due to changes in their permeability. It was found that the high concentration of EDTA and toluene decreased the luminescence and caused the condensation of DNA-fibrils and the cell damage after long-term and short-term action. The low concentration of EDTA and toluene did not decrease the bacterial luminescence; the noticeable damage of cell membranes did not take place during short-term treatment. However, the long action of these substances changed the membrane permeability resulting in increased sensitivity of bacterial luminescence to some toxic substances., (Copyright 1999 John Wiley & Sons, Ltd.)

The examination of four species of luminous bacteria Photobacterium leiognathi, Photobacterium phosphoreum, Vibrio fischeri and Vibrio harveyi has enabled us to reveal some nutrient medium components effecting growth, luminescence intensity and luciferase synthesis. These agents are nucleic components (nucleotides, nucleotides and amine bases), amino acids and vitamins, which are part of hydrolysates from the biomass of various lithotrophic microorganisms, hydrogen-oxidizing, iron-oxidizing and carboxydobacteria. The effect of promoting agents essentially alters the physiological state and ultrastructure of the cells of luminous bacteria and increases luciferase biosynthesis two- to three-fold compared to a control.

The luminescent cells of Photobacterium were studied by electron microscopy in order to establish what caused their sticking together and growth on the glass walls of the vessel during continuous cultivation. Electron microscopy revealed protrusions, of various shape and size, on the cells. The phenomenology of various protrusions, including fimbria, is described, and the effect of cultivation conditions (continuous culture, periodic culture) and growth phases on their emergence was elucidated. The sticking of the cells together and their growth on the glass walls were less expressed at pH between 7.5 and 7.9, when the amount of the cells with the fimbria was the least and they were formed during the later phase of growth.