o energy shortage in cells and the toxicity to the soil-living microarthropods Xenylla grisea (Hypogastruridae) and Folsomia candida (Isotomidae) was established by . In this context, it seemed interesting to correlate the energy shortage in cells of aquatic organisms caused by a given pesticide to the equilibrium constant Kc for complexation with ATP. Therefore, the values of Kc given in Tables 2 and 3 will be used to characterize the above energy shortage in cells.
In Figure 5, the toxicity T towards the bacteria B. harveyi as a function of Kc for complexation with ε-ATP at various C (from 10–1 to 10–3 М) is seen to be directly proportional.
The toxicity K towards the cells of T. pyriformis as a function of Kc is shown in Figure 6. Again, the K values
Figure 5. Correlation of the toxicity of pesticides with respect to luminescent bacteria with the values of constant of [e-АТP-pesticide] complex formation (Kc) for pesticide concentrations: 1—10−1 М; 2—10−2 М; 3—10−3 М. S—Sencor; L—Lontrel; B—Bentazon; R—Glyphosate; H—Hymexazol.
Figure 6. Correlation of the toxicity of pesticides with respect to infusoria with the values of constant of [e-АТPpesticide] complex formation (Kc) for pesticide concentrations: 1—10−1 М; 2—10−2 М; 3—10−3 М; S—Sencor; L— Lontrel; B—Bentazon; R—Glyphosate; H—Hymexazol.
are seen to be proportional to Kc over the entire range of C (from 10–1 to 10–3 М).
The toxicity of metal complexes towards B. harveyi and T. pyriformis as a function of Kc are shown in Figures 7 and 8, respectively, as a series of parallel linear plots. With increasing Kc, the toxicity of the complexes under study is seen to increase proportionally over the entire range of C (10–1 - 10–7 М).
The ЕС50 values as a function of Kc for our pesticides are given in Figure 9. Using this plot, we attempted to predict the ЕС50 values based on a known magnitude of
Figure 7. Correlation of the toxicity of Lontrel-metal complexes with respect to luminescent bacteria with the values of constant of [e-АТP-MetL2] complex formation (Kc) for Lontrel-metal complexes concentrations: 1—10−1 М; 2— 10−2 М; 3—10−3 М.
Figure 8. Correlation of the toxicity of Lontrel-metal complexes with respect to infusoria with the values of constant of [e-АТP-MetL2] complex formation (Kc) for Lontrelmetal complexes concentrations: 1—10−1 М; 2—10−2 М; 3— 10−3 М.
Kc. For this purpose, we drew the reported values of Kc for Kuzagard, Setoxydime, and Tilt onto curve 1 in Figure 9. Our curve 1 predicts that for the above compounds the ЕС50 values must attain the values of 1.0 × 10–2, 3.4 × 10–2, and 1.1 М, respectively.
Just as for pesticides, we compared the behavior of the complexes at the same ЕС50 value and plotted the de pendence of this ЕС50 on Kc (Figure 10). Apparently, this plot holds true for the metal complexes with a given ligand (L). This dependence is universal: it relates the
Figure 9. Regularity of the dependences of the values ЕС50 of pesticides with respect to infusoria on values of constant of complex formation (Kc): (○) our data points for the infusoria Tetrahymena pyriformis and the reported data for (·) zooplankton Daphnia magna ; (☆) juvenile fish Lepomis macrochirus up to 0.4 cm in size , () juvenile fish Oncorhynchus mykiss [21,34], () adult fish Oncorhynchus mykiss [21,24,28-30], and (■) adult fish Cyprinodon variegates [21,22,28,32,33,35].
Figure 10. Regularity of the dependences of the toxicity of Lontrel-metal complexes with respect to infusoria on values of constant of complex formation (Kc).
energy shortage in cell caused by that or another Plt to the acute toxicity of a given Plt. and “principle”.
3.4. Relationship between Available Experimental and Literature Data
It seemed interesting to check out the universality of the above relationship on the available set of relevant data (Table 4). For the water flea Scapholeberis kingi, the LC50 value for Roundup is seen to be lower than Bentazon. However, for the opossum Americamysis bahia, the LC50 values well correlate with Kc for the complexation of ATP with Roundup, Setoxydime, Bentazon, and Tilt.
Despite a wide use of Lontrel in agriculture, information about its toxicity is virtually lacking in the literature. The available data for the simplest ciliated T. pyriformis  and T. thermophila [16-18] indicate that the toxicity of Lontrel is higher than that of Hymexazol by a factor of 5 - 10 (EC50 = 104.6 × 10–6 g/l = 0.54 × 10–6 М and 500 × 10–6 g/l = 5.05 × 10–6 М, respectively). According to our data, this difference is only 2 - 2.5 times. Our data for the infusoria demonstrate the ability of the pesticides under study to complexation with ATP. The reported data for zooplankton Daphnia magna are summarized in Figure 9. Our curve 1 and the EC50 values reported by different workers for six pesticides are seen to correlate.
The reported LC50 values for Crustacea are collected in Table 5. The toxicity of Roundup (to Orconectes nais), Hymexazol (to Decapoda), and Tilt (to Procambarus sp.) are seen to decrease in the above order according to our Kc values for these compounds.
The LC50 values for different fishes are summarized in Table 6 and Figure 9. As follows from Figure 9, our curve 1 well agrees with the available data for zooplankton and fish. These data also confirm a correlation between the Plt toxicity and the molecular mechanism of their action, namely, ATP binding in living cells.
As known, on the one hand, all living organisms, including fish, possess a unique system for excretion of foreign chemical compounds . On the other hand, the pollutants under study influence not only on luciferase but also on the entire system of redox enzymes [19,20], free pool of metals , and nucleotides [4,5]. The whole set of biochemical reactions proceeds simultaneously, so that homeostasis is completely suppressed. The processes suppressing all functions of the organism increase in a geometric progression. All this leads to an increase in the toxicologic effect in vivo, i.e., to lower effective concentrations of pollutants. This circumstance can explain a different order for a decrease in Kc for the pesticides under study and ATP and in the toxicity of these compounds. Nevertheless, a correlation between the toxicity and Kc values was found to be well pronounced for all representatives of aquatic life.
Table 4. Toxic effect of pesticides on different zooplankton species (LC50, from literary data).
Table 5. Toxic effects of pesticides on crustacea (LC50, from literary data).
Table 6. Toxicity of pesticides with respect to fishes (mortality—LC50, from literary data).
Therefore, our data suggest that, upon ingress of Plt, pesticides, and their metal complexes in living organism, these compounds undergo chemical binding with ATP to give stable Plt-ATP complexes with their own Kc value. Such bioorganic complexes infringe energy metabolism in a living organism. The cells suffer from energy shortage, which leads to the death of the cells and sequentially of the entire organism. Such a mechanism of action manifests itself as a decrease in the enzymatic activity of bacteria or in the reproductive function of infusoria.
The established toxicity—Kc relationship was found to hold true for a wide variety of multicellular organisms. This relationship can be used for express-evaluation of pollutant toxicity towards representatives of aquatic life.
1) The toxicity factors of pesticides, viz., Lontrel, Sencor, Roundup, Bentazon, and Hymexazol and also Lontrel complexes with Cu, Co, Mn, Mg, Mo, Ni, and Zn towards the bacteria Beneckea harveyi and infusoria Tetrahymena pyriformis were measured.
2) The concentration dependence of the above toxicity factors was determined.
3) At any concentration, the toxicity of the pesticides was found to increase in the following order: Sencor > Lontrel > Roundup > Bentazon > Hymexazol, while that of the MetL2 complexes is as follows: CuL2 > CoL2 > NiL2 > MoL2 > MnL2 > ZnL2 > MgL2. The toxicity of MetL2 complexes is higher (except for MgL2) than that of free Lontrel.
4) Toxicity of that or another man-caused pollutant was found to be directly related to the energy shortage arising in cells under the action of pollutant complexes with ATP at the molecular level.