335
Microbial Tests
Microbes, especially bacteria (Salmonella) are most frequently used in vitro to
study the biological properties of PAHs. Based on the mutation properties, Ames
test and umu test are widely used to screen out carcinogenic and mutagenic PAHs
and ePAH, respectively. Salmonella typhimurium forms colonies in histidine specific agar plates when exposed to chemicals. Mammalian microsomal enzymes are
added to increase the metabolic activity as some carcinogenic chemicals need metabolic enzymes to be activated. After the carcinogens were activated, the DNA damage is quantitated based on the β-galactosidase activity using colorimetric assay
[89]. Chemiluminescence assay, in which luminescent bacteria produce light when
exposed, is also used in the microbial test to check the biological activity of PAHs.
The LUMIStox, ToxAlert, and Microtox bioassays are also based on similar principles in which a decrease in the luminescence rate by PAHs toxicants is quantified
by the decrease in the respiration rate of bacteria used [90]. These are the most common tests used to check various biological effects of PAHs, the results are highly
variable depending on the assay used, specificity, durability of chemicals, and sensitivity of test but the advantages of these assays are that they are less expensive and
less time-consuming.
In Vitro Cell Assay
Different types of cells are used to detect the adverse biological activities of PAHs;
luciferase gene expression assay is frequently used to detect the PAHs in various
samples including water, soil, sediments, etc. To check DNA damage and its repair,
migration with high sensitivity and specificity, comet assay is used. Flow cytometry
is also the simplest and widely used assay in cell lines to significantly check chromosomal damage and genotoxic property of PAHs [91].
Plasmid Vector Reporter Gene Assay
Various plasmids or recombinant yeasts are constructed which acts as a vector,
equipped with different kinds of reporter genes for biological markers (both for
proteins and genes) which bind to their corresponding receptors or ligands and the
biological activity of PAHs is quantified by molecular based studies. Biological
effects such as estrogenicity, carcinogenicity, toxicity rate, and some other activities
of PAHs are used using different cell lines and reporter genes.
19 Role of Polycyclic Aromatic Hydrocarbons as EDCs in Metabolic Disorders
Microbial Tests
Microbes, especially bacteria (Salmonella) are most frequently used in vitro to
study the biological properties of PAHs. Based on the mutation properties, Ames
test and umu test are widely used to screen out carcinogenic and mutagenic PAHs
and ePAH, respectively. Salmonella typhimurium forms colonies in histidine specific agar plates when exposed to chemicals. Mammalian microsomal enzymes are
added to increase the metabolic activity as some carcinogenic chemicals need metabolic enzymes to be activated. After the carcinogens were activated, the DNA damage is quantitated based on the β-galactosidase activity using colorimetric assay
[89]. Chemiluminescence assay, in which luminescent bacteria produce light when
exposed, is also used in the microbial test to check the biological activity of PAHs.
The LUMIStox, ToxAlert, and Microtox bioassays are also based on similar principles in which a decrease in the luminescence rate by PAHs toxicants is quantified
by the decrease in the respiration rate of bacteria used [90]. These are the most common tests used to check various biological effects of PAHs, the results are highly
variable depending on the assay used, specificity, durability of chemicals, and sensitivity of test but the advantages of these assays are that they are less expensive and
less time-consuming.
In Vitro Cell Assay
Different types of cells are used to detect the adverse biological activities of PAHs;
luciferase gene expression assay is frequently used to detect the PAHs in various
samples including water, soil, sediments, etc. To check DNA damage and its repair,
migration with high sensitivity and specificity, comet assay is used. Flow cytometry
is also the simplest and widely used assay in cell lines to significantly check chromosomal damage and genotoxic property of PAHs [91].
Plasmid Vector Reporter Gene Assay
Various plasmids or recombinant yeasts are constructed which acts as a vector,
equipped with different kinds of reporter genes for biological markers (both for
proteins and genes) which bind to their corresponding receptors or ligands and the
biological activity of PAHs is quantified by molecular based studies. Biological
effects such as estrogenicity, carcinogenicity, toxicity rate, and some other activities
of PAHs are used using different cell lines and reporter genes.
19 Role of Polycyclic Aromatic Hydrocarbons as EDCs in Metabolic Disorders