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Bacterial biosensors
Abstract:
Industrialisation
and new technologies have not only made life more convenient for
humans, but have also created various environmental problems,
potentially posing serious health problems
to living organisms, including people. Organic compounds,
originating mostly from the use of petroleum products, are highly
toxic and cause concern for soil and drinking water quality. In
recent years, bacterial whole cell biosensors have been developed
as tools to detect and quantify the toxicity of samples from
different environments. It seems that promoter sequences of
bacterial heat shock proteins genes are very suitable in bacterial
biosensors construction. Exposure of E. coli
cells to higher temperature
or other environmental stresses (viral infection, antibiotics,
methylating and
alkylating agents, hydrogen peroxide and various pollutant
molecules such as aromatic compounds or heavy metals)
trigger increased expression of stress proteins, including heat
shock response. When the
specific compounds arê present in the environment, that may
cause the changes in promoters of stress proteins, and
in the reporter gene expression in all cells. This model of action
was used in construction of
whole-cell genetically engineered microorganisms (GEMs) called biosensors.
In this paper, bacteria strains, which contain such specific
genetic fusion of promoters regions
of heat shock proteins genes or promoters regions of different
chemicals resistance genes and gfp
(green fluorescent protein), lux from Vibrio
fischeri (encoding luciferase) or lacZ
(encoding b-galactosidase)
reporters were described. Some application possibilities of
bacteria strains with those gene
constructs for detection and estimation the bioavailability
and toxicity of different pollutants in
the environment were characterised.
1. Introduction.
2. The kinds of bacterial biosensors. 3. Stress as an
inducer of heat shock proteins synthesis.
4. The response of bacterial cells-biosensors to different
compounds. 5. Conditions of fluorescent
cell response analyses. 6. Summary |
