Bioluminescent System of Luminous Bacteria for Detection of Microbial Contamination

Microbial contamination is usually analyzed using luciferin-luciferase system of fireflies by the detection of adenosine-5’-triphosphate (ATP). There is an opportunity to assess the bacterial contamination of various objects based on a quantitative analysis of other nucleotides. In the present study, a bioluminescent enzyme system of luminous bacteria NADH:FMN-oxidoreductase (Red) and luciferase (BLuc) was investigated to understand if it can be used for quantitative measurements of bacterial cells by nicotinamide adenine dinucleotide (NADH) and flavin mononucleotide (FMN) detection. To increase the sensitivity of bioluminescent system to FMN and NADH, optimization of assay conditions was performed by varying enzymes and substrates concentrations. The lowest limits of detection were 1.2 nM FMN and 0.1 pM NADH. Escherichia coli cells were used as a model bacterial sample. FMN and NADH extraction was made by destructing cell membrane by ultrasonication. Cell suspension was added into the reaction mixture instead of FMN and NADH, and light intensity depended on number of bacterial cells in the reaction mixture. Centrifugation of sonicated sample as an additional step of sample preparation did not improve the sensitivity of method. The experimental results showed that Red and BLuc system could detect at least 800 thousand bacterial cells mL-1 by determining concentration of NADH extracted from lysed cells, while 3.9 million cells mL-1 can be detected by determining concentration of FM

Toxicity of Different Types of Surfactants via Cellular and Enzymatic Assay Systems

Surfactants have a widespread occurrence, not only as household detergents, but also in their application in industry and medicine. There are numerous bioassays for assessing surfactant toxicity, but investigations of their impact on biological systems at the molecular level are still needed. In this paper, luminous marine bacteria and their coupled NAD(P)H:FMN-oxidoreductase + luciferase (Red + Luc) enzyme system was applied to examine the effects of different types of surfactants, including cationic cetyltrimethylammonium bromide (CTAB), non-ionic polyoxyethylene 20 sorbitan monooleate (Tween 80) and anionic sodium lauryl sulfate (SLS), and to assess whether the Red + Luc enzyme system can be used as a more sensitive indicator of toxicity. It was shown that the greatest inhibitory effect of the surfactants on the activity of luminous bacteria and the Red + Luc enzyme system was in the presence of SLS samples. The calculated IC50 and EC50 values of SLS were 10−5 M and 10−2 M for the enzymatic and cellular assay systems, respectively. The results highlight the benefits of using the enzymatic assay system in ecotoxicology as a tool for revealing surfactant effects on intracellular proteins if the cellular membrane is damaged under a long-term exposure period in the presence of the surfactants. For this purpose, the bioluminescent enzyme-inhibition-based assay could be used as an advanced research tool for the evaluation of surfactant toxicity at the molecular level of living organisms due to its technical simplicity and rapid response time

Биолюминесцентная система светящихся бактерий для анализа микробного загрязнения

Microbial contamination is usually analyzed using luciferin-luciferase system of fireflies by the detection of adenosine-5’-triphosphate (ATP). There is an opportunity to assess the bacterial contamination of various objects based on a quantitative analysis of other nucleotides. In the present study, a bioluminescent enzyme system of luminous bacteria NADH:FMN-oxidoreductase (Red) and luciferase (BLuc) was investigated to understand if it can be used for quantitative measurements of bacterial cells by nicotinamide adenine dinucleotide (NADH) and flavin mononucleotide (FMN) detection. To increase the sensitivity of bioluminescent system to FMN and NADH, optimization of assay conditions was performed by varying enzymes and substrates concentrations. The lowest limits of detection were 1.2 nM FMN and 0.1 pM NADH. Escherichia coli cells were used as a model bacterial sample. FMN and NADH extraction was made by destructing cell membrane by ultrasonication. Cell suspension was added into the reaction mixture instead of FMN and NADH, and light intensity depended on number of bacterial cells in the reaction mixture. Centrifugation of sonicated sample as an additional step of sample preparation did not improve the sensitivity of method. The experimental results showed that Red and BLuc system could detect at least 800 thousand bacterial cells mL-1 by determining concentration of NADH extracted from lysed cells, while 3.9 million cells mL-1 can be detected by determining concentration of FMNДля анализа микробного загрязнения широко используется биолюминесцентный метод, основанный на определении аденозин-5’-трифосфата (АТР) с помощью люциферин- люциферазной системы светляков. Существует принципиальная возможность оценки степени бактериальной обсемененности различных объектов исходя из количественного анализа других нуклеотидов. В работе исследована возможность применения биолюминесцентной системы светящихся бактерий NADH:FMN-оксидоредуктаза (Red) и люцифераза (BLuc) для количественного анализа бактериальных клеток путем определения количества никотинамидадениндинуклеотида (NADH) и флавинмононуклеотида (FMN) в образце. Для увеличения чувствительности биолюминесцентной системы к FMN и NADH осуществлена оптимизация условий проведения анализа путем подбора концентраций ферментов и субстратов в реакционной смеси. Максимальная чувствительность биферментной системы Red + BLuc составила 1,2 нМ FMN и 0,1 пМ NADH. Для проведения количественного анализа бактериальных клеток использовали модельный бактериальный образец – культуру Escherichia coli. Экстрагирование FMN и NADH проводили путем разрушения клеточной мембраны ультразвуковым дезинтегратором. Клеточную суспензию добавляли в реакционную смесь вместо раствора FMN или NADH, при этом интенсивность свечения биолюминесцентной системы зависела от количества бактериальных клеток в реакционной смеси. Введение в пробоподготовку дополнительной процедуры центрифугирования образца, подвергнутого ультразвуковой обработке, не привело к увеличению чувствительности метода. Таким образом, было показано, что чувствительности биферментной системы Red + BLuc достаточно для определения не менее 800 тыс бактериальных клеток в миллилитре путем экстрагирования NADH из разрушенных клеток. При анализе, основанном на определении концентрации FMN в бактериальном образце, чувствительность метода составила 3,9 млн клеток на миллилит

Биолюминесцентная система светящихся бактерий для анализа микробного загрязнения

Microbial contamination is usually analyzed using luciferin-luciferase system of fireflies by the detection of adenosine-5’-triphosphate (ATP). There is an opportunity to assess the bacterial contamination of various objects based on a quantitative analysis of other nucleotides. In the present study, a bioluminescent enzyme system of luminous bacteria NADH:FMN-oxidoreductase (Red) and luciferase (BLuc) was investigated to understand if it can be used for quantitative measurements of bacterial cells by nicotinamide adenine dinucleotide (NADH) and flavin mononucleotide (FMN) detection. To increase the sensitivity of bioluminescent system to FMN and NADH, optimization of assay conditions was performed by varying enzymes and substrates concentrations. The lowest limits of detection were 1.2 nM FMN and 0.1 pM NADH. Escherichia coli cells were used as a model bacterial sample. FMN and NADH extraction was made by destructing cell membrane by ultrasonication. Cell suspension was added into the reaction mixture instead of FMN and NADH, and light intensity depended on number of bacterial cells in the reaction mixture. Centrifugation of sonicated sample as an additional step of sample preparation did not improve the sensitivity of method. The experimental results showed that Red and BLuc system could detect at least 800 thousand bacterial cells mL-1 by determining concentration of NADH extracted from lysed cells, while 3.9 million cells mL-1 can be detected by determining concentration of FMNДля анализа микробного загрязнения широко используется биолюминесцентный метод, основанный на определении аденозин-5’-трифосфата (АТР) с помощью люциферин- люциферазной системы светляков. Существует принципиальная возможность оценки степени бактериальной обсемененности различных объектов исходя из количественного анализа других нуклеотидов. В работе исследована возможность применения биолюминесцентной системы светящихся бактерий NADH:FMN-оксидоредуктаза (Red) и люцифераза (BLuc) для количественного анализа бактериальных клеток путем определения количества никотинамидадениндинуклеотида (NADH) и флавинмононуклеотида (FMN) в образце. Для увеличения чувствительности биолюминесцентной системы к FMN и NADH осуществлена оптимизация условий проведения анализа путем подбора концентраций ферментов и субстратов в реакционной смеси. Максимальная чувствительность биферментной системы Red + BLuc составила 1,2 нМ FMN и 0,1 пМ NADH. Для проведения количественного анализа бактериальных клеток использовали модельный бактериальный образец – культуру Escherichia coli. Экстрагирование FMN и NADH проводили путем разрушения клеточной мембраны ультразвуковым дезинтегратором. Клеточную суспензию добавляли в реакционную смесь вместо раствора FMN или NADH, при этом интенсивность свечения биолюминесцентной системы зависела от количества бактериальных клеток в реакционной смеси. Введение в пробоподготовку дополнительной процедуры центрифугирования образца, подвергнутого ультразвуковой обработке, не привело к увеличению чувствительности метода. Таким образом, было показано, что чувствительности биферментной системы Red + BLuc достаточно для определения не менее 800 тыс бактериальных клеток в миллилитре путем экстрагирования NADH из разрушенных клеток. При анализе, основанном на определении концентрации FMN в бактериальном образце, чувствительность метода составила 3,9 млн клеток на миллилит

The Effects of Commercial Pesticide Formulations on the Function of In Vitro and In Vivo Assay Systems: A Comparative Analysis

Pesticides are commonly used in agriculture and are an important factor of food security for humankind. However, the overuse of pesticides can harm non-target organisms, and, thus, it is vital to comprehensively study their effects on the different metabolic pathways of living organisms. In the present study, enzyme-inhibition-based assays have been used to investigate the effects of commercial pesticide formulations on the key enzymes of the organisms, which catalyze a wide variety of metabolic reactions (protein catabolism, lactic acid fermentation, alcohol metabolism, the conduction of nerve impulses, etc.). Assay conditions have been optimized, and the limitations of the methods used in the study, which are related to the choice of the solvent for commercial pesticide formulations and optical effects occurring when commercial pesticide formulations are mixed with solutions of enzymes and substrates of assay systems, have been revealed. The effects of commercial pesticide formulations on simple chemoenzymatic assay systems (single-enzyme reactions) have been compared to their effects on complex multicomponent molecular systems (multi-enzyme reactions) and organisms (luminescent bacterium). The in vitro assay systems have shown higher sensitivity to pesticide exposure than the in vivo assay system. The sensitivity of the in vitro assay systems increases with the elongation of the chain of conjugated chemoenzymatic reactions. The effects exerted by commercial pesticide formulations with the same active ingredient but produced by different manufacturers on assay system functions have been found to differ from each other

Enzyme Inhibition-Based Assay to Estimate the Contribution of Formulants to the Effect of Commercial Pesticide Formulations

Pesticides can affect the health of individual organisms and the function of the entire ecosystem. Therefore, thorough assessment of the risks associated with the use of pesticides is a high-priority task. An enzyme inhibition-based assay is used in this study as a convenient and quick tool to study the effects of pesticides at the molecular level. The contribution of formulants to toxicological properties of the pesticide formulations has been studied by analyzing effects of 7 active ingredients of pesticides (AIas) and 10 commercial formulations based on them (AIfs) on the function of a wide range of enzyme assay systems differing in complexity (single-, coupled, and three-enzyme assay systems). Results have been compared with the effects of AIas and AIfs on bioluminescence of the luminous bacterium Photobacterium phosphoreum. Mostly, AIfs produce a considerably stronger inhibitory effect on the activity of enzyme assay systems and bioluminescence of the luminous bacterium than AIas, which confirms the contribution of formulants to toxicological properties of the pesticide formulation. Results of the current study demonstrate that “inert” ingredients are not ecotoxicologically safe and can considerably augment the inhibitory effect of pesticide formulations; therefore, their use should be controlled more strictly. Circular dichroism and fluorescence spectra of the enzymes used for assays do not show any changes in the protein structure in the presence of commercial pesticide formulations during the assay procedure. This finding suggests that pesticides produce the inhibitory effect on enzymes through other mechanisms

Enzyme Inhibition-Based Assay to Estimate the Contribution of Formulants to the Effect of Commercial Pesticide Formulations

Pesticides can affect the health of individual organisms and the function of the entire ecosystem. Therefore, thorough assessment of the risks associated with the use of pesticides is a high-priority task. An enzyme inhibition-based assay is used in this study as a convenient and quick tool to study the effects of pesticides at the molecular level. The contribution of formulants to toxicological properties of the pesticide formulations has been studied by analyzing effects of 7 active ingredients of pesticides (AIas) and 10 commercial formulations based on them (AIfs) on the function of a wide range of enzyme assay systems differing in complexity (single-, coupled, and three-enzyme assay systems). Results have been compared with the effects of AIas and AIfs on bioluminescence of the luminous bacterium Photobacterium phosphoreum. Mostly, AIfs produce a considerably stronger inhibitory effect on the activity of enzyme assay systems and bioluminescence of the luminous bacterium than AIas, which confirms the contribution of formulants to toxicological properties of the pesticide formulation. Results of the current study demonstrate that “inert” ingredients are not ecotoxicologically safe and can considerably augment the inhibitory effect of pesticide formulations; therefore, their use should be controlled more strictly. Circular dichroism and fluorescence spectra of the enzymes used for assays do not show any changes in the protein structure in the presence of commercial pesticide formulations during the assay procedure. This finding suggests that pesticides produce the inhibitory effect on enzymes through other mechanisms