Devard I. Stom

Bioluminescent method in studying the complex effect of sewage components.

The inhibition of bacterial luminescence has been used in testing industrial enterprises sewage. The toxicity of the sewage is less than the total toxicity of separate components due to neutralization of quinone products of polyphenol oxidation in the reactions with the other phenol components of sewage. Toxicity increase is due to their influence on the cell membrane. Studies of cell ultrastructure confirm this fact. The studied mechanism of the complex effect allowed a more accurate forecast of the ecological situation during the discharge of phenol compounds and metals. It also showed the necessity of taking into account the complex effect of sewage components on contaminant discharge into water reservoirs.

Effect of humic substances on toxicity of inorganic oxidizer bioluminescent monitoring

The current study deals with the effect of humic substances (HS) on toxicity of solutions of a model inorganic oxidizer, potassium ferricyanide. Chemical reactions responsible for toxicity changes are under consideration. The bioluminescent system of coupled enzymatic reactions catalyzed by bacterial luciferase and oxidoreductase was used as a bioassay. General and oxidative toxicity of ferricyanide solutions were evaluated. Ability of HS to decrease or increase general and oxidative toxicity of the solutions was revealed. Two types of chemical processes are supposed to be responsible for detoxification by HS: ferricyanide-HS complex formation and acceleration of endogenous redox reactions in the bioluminescent assay system. Decrease of oxidative toxicity of ferricyanide solution was observed under incubation with HS at all concentrations of HS used. Conditions for general toxicity decrease were prior incubation of ferricyanide with HS and low HS concentrations (< 10⁻⁴g/L). Acceleration of NADH auto-oxidation under higher HS concentrations was supposed to result in a toxicity increase.

Bioluminescence as a tool for studying detoxification processes in metal salt solutions involving humic substances

The paper considers effects of humic substances (HS), as natural attenuators of toxicity, on solutions of model inorganic pollutants, metal salts - Pb(NO(3))(2), СоСl(2), CuSO(4), Eu(NO(3))(3), СrСl(3), and K(3)[Fe(СN)(6)]. Luminous bacteria Photobacterium phosphoreum and bioluminescent system of coupled enzymatic reactions were used as bioassays to monitor toxicity of salt solutions. The ability of HS to decrease or increase toxicity was demonstrated. Detoxifying concentrations of HS were determined; detoxification coefficients were calculated at different times of exposure of salt solutions to HS. To study the combined effects of HS and salts on bioluminescent assay systems, the rates of biochemical reactions and bacterial ultrastructure were analyzed. The detoxifying effects were explained by: (1) decrease of free metal content in water solutions under metal-HS binding; (2) increase of biochemical reaction rates in a bioluminescent assay system under HS effect; (3) enhancement of mucous layers on cell surface as a response to unfavorable impact of toxicants. Detoxifying mechanisms (2) and (3) reveal the active role of bioassay systems in detoxification processes.

Detoxication of solutions of organic oxidants by humic substances: bioluminescence monitoring.

The search for the methods of detoxication is a keydirection in modern ecology and biotechnology. One ofthe possible ways of detoxication of pollutants may bethe use of humic substances—the products of naturaltransformation of various organic substances. Today,more and more data on the ability of humic substancesto decrease the detrimental influence of toxicantsappear [1, 2]. Earlier, the effect of detoxication wasstudied using classic test systems, such as fish, algae,crustaceans, and plants [2–6].However, despite the long-term experience of study-ing the properties of humic substances, the question onthe mechanism of the detoxicating effect of humic sub-stances remains open. It was assumed that the detoxi-cating properties of humic substances are determinedby their ability to reduce oxidants. The presence inhumic substances of phenolic groups and fragmentscarrying unpaired electrons allows to assume the possi-bility of transition (in particular, bivalent mercury) intoreduced and, respectively, less toxic forms upon inter-action with humic substances [7, 8]. It was alsoassumed that toxicants are bond by humic substances,which prevents penetration of such large aggregatesinto cells [9].To study the mechanisms of detoxication of toxi-cants by humic substances in detail, simple test systems(such as luminous bacteria) are especially promising.They have great advantages over the biotests that wereused earlier due to high rate of analysis, sensitivity,simplicity, and possibility of instrumental recording oftoxicity.This study is devoted to investigation of the mecha-nism of detoxication of solutions of organic oxidantsusing humic substances. Quinones—the products ofoxidation of the very widely spread organic pollutants,phenols, were chosen as model organic substances.MATERIALS AND METHODSIn this study, we used a series of quinones with dif-ferent redox characteristics: 1,4-benzoquinone, tet-rafluoro-1,4-benzoquinone, methyl-1,4-benzoquinone,tetramethyl-1,4-benzoquinone, and 1,4-naphto-quinone.The toxicity of quinones was assessed using thebioluminescence biotest Microbiosensor 677F [10],which is based on lyophilized luminous bacteria

Mathematical Modelling of Perturbations of the Lake Baikal Ecosystem and Identification of the Model on the Basis of Experiments

This paper presents a perspective direction in investigations at the cross-point of such sciences as biology, mathematical modelling, ecotoxieology, system analysis. Presently, we developed a complex of mathematical models of different levels. The technology of information filling of the model of ecosystem’s anthropogenic perturbations, which is based on goal-oriented experiments determined by the type of model, and also algorithms of object identification through a series of experiments, are elaborated. A technology of constructing model ecosystems (so called physics models) for studying the response of separate subsystems and of the whole ecosystem to anthropogenic affects is proposed. A methodic forecasting scenario of anthropogenic affects on the ecosystem of Lake Baikal is computed.