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Luminescent bacteria–based biosensors are widely used for fast and sensitive monitoring of food safety, water quality, and other environmental pollutions. Recent advancements in biomedical engineering technology have led to improved portability, integration, and intelligence of these biotoxicity assays. Moreover, genetic engineering has played a significant role in the development of recombinant luminescent bacterial biosensors, enhancing both detection accuracy and sensitivity. This review provides an overview of recent advances in the development and applications of novel luminescent bacteria–based biosensors, and future perspectives and challenges in the cutting‐edge research, market translation, and practical applications of luminescent bacterial biosensing are discussed. [ABSTRACT FROM AUTHOR]

Bioluminescence refers to light produced by living organisms, including some species of bacteria of marine origin. The mechanism of bacterial luminescence is given by a biochemical reaction in which luciferin, oxygen, the enzyme luciferase and ATP participate, to result in the emission of light and the formation of water. The expression of the Lux genes that encode the enzymatic machinery is regulated for some species by quorum sensing, a phenomenon that allows light emission to only occur when there is a high cell density. Chemical and biological contaminants, as well as some physical factors in the environment can affect the luminescence emission. Given their sensitivity to environmental conditions and low toxicity, luminescent bacteria have been employed in a wide variety of fields, including gene expression analyses, drug discovery, studies of protein dynamics, mapping of signal transduction pathways and environmental monitoring. The objective of this review is to present the state of research on the phenomenon of bioluminescence, with a special focus on luminescent marine bacteria and their potential application in the field of biotechnology and environmental monitoring.. [ABSTRACT FROM AUTHOR]

Introduction. Currently, the search for new antibacterial substances is an urgent task due to the growing resistance of pathogens to existing antibiotics. One of the key directions in this area is the expansion of scientific research of medicinal plants, as new sources of therapeutic agents. This article examines the possibility of using highly sensitive bioluminescent test bacteria for these purposes, which can quickly detect non-specific antimicrobial activity and can be adapted to highly effective pharmaceutical screening technologies.Aim. To study the applicability of bioluminescent bacteria for the analysis of the antibacterial activity of biologically active substances (BAS) of plant origin.Materials and methods. BAS quercetin, 8-hydroxyquinoline, gallic acid and thymoquinone, which are often found in medicinal plant raw materials and with which its antibacterial properties are associated, were used in the work. Bacteria with constitutive bioluminescence Aliivibrio fischeri F1 and Escherichia coli (pXen7), as well as recombinant bioreporter strains with inducible luminescence were used as test-objects: E. coli (pRecA-lux), E. coli (pColD-lux), reacting to nucleic acid damage; E. coli (pKatG-lux) and E. coli (pSoxS-lux), sensitive to oxidative stress.Results and discussion. It was found that the nonspecific antimicrobial activity of the studied BAS is manifested in the inhibition of bacterial bioluminescence of test-strains with constitutive glowing. It was noted that the marine test-bacteria A. fischeri F1 have significantly greater sensitivity to the action of BAS, compared with the recombinant strain of E. coli (pXen7). It has been shown that their inhibitory effect begins at concentrations of 2 mcg/ml, and bactericidal activity occurs at concentrations of more than 20 mcg/ml. The results obtained are compared with the data on MIC and MBC of gram(+) and gram(–) pathogens. The study of the induction of bioluminescence of recombinant bioreporter strains showed that the antibacterial effect of the BAS is accompanied by oxidative stress. Also, quercetin caused activation of luminescence in E. coli (pRecA-lux) and E. coli (pColD-lux), which may indicate its participation in damage to nucleic acids. Analysis of the induction factors of bioreporter strains indicates that the revealed mechanisms of antibacterial activity are not major, but may be of a secondary nature.Conclusion. It has been shown that the intensity of the glow of natural and recombinant bioluminescent bacteria can be an indicator of the antibacterial activity of BAS of natural origin. The high sensitivity of A. fischeri F1 bacteria to the action of substances such as quercetin, 8-hydroxyquinoline, gallic acid and thymoquinone has been shown. Considering that bioluminescence analysis is a quantitative instrumental method, it can be easily adapted for high-throughput pharmaceutical screening. It has been shown that the luminescence intensity of natural and recombinant bioluminescent bacteria can be an indicator of the antibacterial activity of BAS of natural origin. The high sensitivity of A. fischeri F1 to the action of substances such as quercetin, 8-hydroxyquinoline, gallic acid and thymoquinone has been established. Taking in an account that bioluminescent analysis is a quantitative instrumental method, it can be easily adapted for high-throughput pharmaceutical screening.

The light emitted by a luminescent bacterium serves as a unique native channel of information regarding the intracellular processes within the individual cell. In the presence of highly sensitive equipment, it is possible to obtain the distribution of bacterial culture cells by the intensity of light emission, which correlates with the amount of luciferase in the cells. When growing on rich media, the luminescence intensity of individual cells of brightly luminous strains of the luminescent bacteria Photobacterium leiognathi and Ph. phosporeum reaches 104–105 quanta/s. The signal of such intensity can be registered using sensitive photometric equipment. All experiments were carried out with bacterial clones (genetically homogeneous populations). A typical dynamics of luminous bacterial cells distributions with respect to intensity of light emission at various stages of batch culture growth in a liquid medium was obtained. To describe experimental distributions, a phenomenological model that links the light of a bacterial cell with the history of events at the molecular level was constructed. The proposed phenomenological model with a minimum number of fitting parameters (1.5) provides a satisfactory description of the complex process of formation of cell distributions by luminescence intensity at different stages of bacterial culture growth. This may be an indication that the structure of the model describes some essential processes of the real system. Since in the process of division all cells go through the stage of release of all regulatory molecules from the DNA molecule, the resulting distributions can be attributed not only to luciferase, but also to other proteins of constitutive (and not only) synthesis.

At the beginning of the paper, the level of necessary phenomenology of complex models is discussed. When working with complex systems, which of course include living organisms and ecological systems, it is necessary to use a phenomenological description. An illustration of the phenomenological approach is given, which captures the most significant general principles or patterns of interactions; the specific values of the parameters cannot be calculated from the first principles, but are determined empirically. An appropriate interpretation is also chosen empirically and pragmatically. However, in order to simulate a wider range of situations, it becomes necessary to lower the level of phenomenology, switch to a more detailed description of the system, introducing interaction between selected elements of the system. The requirements for a system model combining ecological, metabolic and genetic levels of cell culture description are formulated. A mathematical model of quorum sensing dynamics during the growth of batch culture of luminescent bacteria at different concentrations of the nutrient substrate has been developed. The model contains four blocks describing ecological, energy, quorum and luminescent aspects of bacterial culture growth. The model demonstrated good agreement with the experimental data obtained. When analyzing the model, three oddities in the behavior of the culture were noted, which presumably can change the idea of some processes taking place during the development of a culture of luminescent bacteria. The results obtained suggest the presence of some additional control system for the luminescent reaction via the synthesis pathways of FMN · Н2 or aliphatic aldehyde. In this case, the generalized description of the contribution of energy metabolism to luminescence only through ATP is too strong a simplification. As a result of comparing the model dynamics with the experiment, a discrepancy arose between the concentration of the substrate (peptone) measured in the experiment and its effective influence on the bacterial population growth. This discrepancy seems to indicate peptone is not the leading substrate, and growth is limited by nutrients contained in the yeast extract, the concentration of which did not change in these experiments. The discrepancies noted between the expectations and the results of experimental data processing, together with the assumptions about the causes of these discrepancies, set the direction for further experimental and theoretical studies of quorum sensing mechanisms in a culture of luminescent bacteria.

The luminescent bacteria bioassay has been commonly used in the detection of environmental pollutants. Compared with traditional chemical and other biological detection methods, the luminescent bacteria bioassay has many demonstrated advantages such as a sensitive response, low cost, high efficiency, and environmental friendliness. The traditional luminescent bacteria bioassay has poor reproducibility and cannot achieve undisturbed soil testing, and the use of leach liquor also affects the results. This paper reviews the research progress and existing issues for the traditional luminescent bacteria bioassay used in the detection of soil pollutants. The luminescence mechanisms and detection principles of three commonly used luminescent bacteria, i.e., Vibrio fischeri, Photobacterium phosphoreum, and Vibrio qinghaiensis, are discussed and compared. In addition, two new luminescent bacteria bioassays are introduced to detect soil pollutants. One method is based on recombinant luminescent bacteria obtained with a gene-modification technique. This method can realize specific detection and enhance sensitivity, but it still cannot achieve undisturbed soil detection. The other method involves using magnetic nanoparticle (MNP)-based biosensors made from luminescent bacteria and MNPs. It can realize the accurate detection of the biological toxicity of the combined pollutants in soil without disturbing the soil's integrity. This study shows that MNP-based biosensors have good application prospects in soil pollution detection, but the mechanism behind their utility still needs to be investigated to realize their popularization and application. [ABSTRACT FROM AUTHOR]

Introduction: Bioremediation has been shown to be an effective strategy for removing toxic pollutants from the environment, particularly organic chemicals such as petroleum hydrocarbons. This paper investigates the changes in toxicity of petroleum-contaminated soil as a result of microbial remediation processes.Methods: Changes in the ecotoxicity of the contaminated soil were examined using a plant, earthworm, enzyme activity and luminescent bacteria toxicity tests.Results: The results showed that bioremediation could effectively degrade petroleum hydrocarbon (C10–C40) pollutants. After 42 days of remediation, the petroleum hydrocarbon (C10–C40) content of Group A (bioaugmented polluted wetland soil) decreased from 1.66 g/kg to 1.00 g/kg, and the degradation rate was 40.6%. The petroleum hydrocarbon (C10–C40) content of Group B (bioaugmented polluted farmland soil decreased from 4.00 g/kg to 1.94 g/kg, and the degradation rate was 51.6%. During the microbial remediation progress, the ecological toxicity of petroleum-contaminated soil first increased and then decreased. The photosynthetic pigment content index in the higher plant toxicity test, the earthworm survival index and the soil catalase activity all showed good agreement with the relative luminescence index of extracted DCM/DMSO in the luminescent bacterial toxicity test. The soil toxicity decreased significantly after remediation. Specifically, the photosynthetic pigment content of wheat were inhibited in the soil during the whole process (remediation for 42 days), and decreased to the minimum on remediation day 21. The 7-day and 14-day survival rate of earthworms in Group A and Group B gradually decreased in the soil remediation process, and then gradually increased, survival rate at the end of remediation was higher than at the beginning. Soil catalase activity was significantly negatively correlated with petroleum hydrocarbon (C10–C40) content (−0.988, −0.989). The ecological toxicity of contaminated soil reached to the maximum on the 21st day of remediation, relative luminosity of luminescent bacteria in dichloromethane/dimethyl sulfoxide extracts from Group A and Group B were 26.3% and 16.3%, respectively.Conclusion: Bioremediation could effectively degrade petroleum hydrocarbon (C10–C40) pollutants. Wheat photosynthetic pigment content, earthworm survival rate, soil catalase activity and relative luminescence of luminescent bacteria can better indicate the ecological toxicity of petroleum-contaminated soil in bioremediation process.

Background: The leaching of substances and the ecotoxic effects of eluates were studied for joint grouts that are based on various types of binders. Eight products, two of them containing either epoxy resin, polybutadiene or polyurethane binders, or modified cement, were investigated using harmonized leaching tests for construction products in combination with ecotoxicity tests on algae, daphnia, luminescent bacteria, fish eggs and mutagenicity in accordance with CEN/TR 17105. In addition to basic parameters, such as pH, TOC, and inorganic components, organic substances in the eluates were analysed by gas and liquid chromatography in combination with mass spectrometry. Quantitative analyses in combination with ecotoxicity data on selected substances were used to deduce which substances cause the observed ecotoxic effects. Results: Different patterns of ecotoxic effects were observed in joint grouts with different binder types. The most ecotoxic effects were observed in epoxy resin-based products, followed by polybutadiene-based products. Fewer ecotoxic effects were observed in polyurethane-based products and modified cements. Some of these showed no ecotoxicity. Some of the substances in the eluates were identified and related to ecotoxic effects. 4-Tert-butylphenol and amines probably contributed to the ecotoxic effects of at least one of the epoxy resin-based renders, whereas cobalt is assumed to contribute to the toxic effect on algae of one of the polybutadiene-based products. However, only some of the leached substances could be identified, and only some of the ecotoxic effects can be explained by the available information on the composition of eluates and known ecotoxic profiles of the identified substances. Conclusions: Ecotoxicity tests on eluates from leaching tests indicate whether environmentally hazardous substances can be leached from construction products. Combined ecotoxicity tests and chemical analysis of eluates from EU-wide harmonized leaching tests for construction products can provide information on substances that cause these effects. This supports the identification and development of environmentally friendly construction products. This study confirmed that ecotoxicity tests in accordance with CEN/TR 17105 are a tool well-suited to support the implementation of the European Commission's zero pollution vision for 2050 and to reduce pollution to levels no longer considered harmful to health and natural ecosystems. [ABSTRACT FROM AUTHOR]

Luminescent bacteria are a fascinating component of marine microbial communities, often related to the light emissions in deep sea marine organisms. They are mainly affiliated with specific phylogenetic groups, such as Photobacterium, Vibrio, and Photorhabdus, and are sometimes involved in symbiotic relationships. However, the luminescence of some marine organisms remains a poorly understood process, and it is not always certain whether their luminescence is attributable to associated luminescent bacteria. In this study, for the first time, luminescent bacteria were isolated from two deep sea organisms, namely, the cephalopod Neorossia caroli and the teleost Chlorophthalmus agassizi. The isolation was carried out on glycerol-supplemented medium, and the search for the luxAB gene was performed on all isolates as a complementary tool to the culture-dependent techniques to detect bioluminescence by molecular approach. The optimum of salinity, temperature, and pH was evaluated by physiological tests for all isolates. The production of extracellular polymeric substances was also preliminarily screened. A total of 24 luminescent isolates were obtained, with an abundance from C. agassizi specimens. All the isolates were taxonomically characterized and were related to different species of Photobacterium, with the exception of Vibrio sp. CLD11 that was from C. agassizi. The luxAB gene was detected in about the 90% of the analysed strains. [ABSTRACT FROM AUTHOR]

In this paper, the releasing characteristics and biological toxicity of Tl, Hg, As and Sb in waste of Lanmuchang mercury-thallium mine were studied. The results indicated that strong acidity can significantly promote the release of Tl from waste. With the increase of pH, the release of Sb grew steadily, while Hg and As showed a trend of first increasing and then decreasing. Fe2(SO4)3 contributed less to the release of As and Sb than to that of Hg and Tl. FeCl3 significantly inhibited the release of As, Sb and Tl. In the leaching experiments of litter and root exudates, the lixiviums appeared neutral, and the litter and root exudates solution significantly reduced the release of Tl, and showed less toxicity to luminescent bacteria. However, they promoted the release of Hg, As and Sb at different levels. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Luminescent bacteria are a fascinating component of marine microbial communities, often related to the light emissions in deep sea marine organisms. They are mainly affiliated with specific phylogenetic groups, such as Photobacterium, Vibrio, and Photorhabdus, and are sometimes involved in symbiotic relationships. However, the luminescence of some marine organisms remains a poorly understood process, and it is not always certain whether their luminescence is attributable to associated luminescent bacteria. In this study, for the first time, luminescent bacteria were isolated from two deep sea organisms, namely, the cephalopod Neorossia caroli and the teleost Chlorophthalmus agassizi. The isolation was carried out on glycerol-supplemented medium, and the search for the luxAB gene was performed on all isolates as a complementary tool to the culture-dependent techniques to detect bioluminescence by molecular approach. The optimum of salinity, temperature, and pH was evaluated by physiological tests for all isolates. The production of extracellular polymeric substances was also preliminarily screened. A total of 24 luminescent isolates were obtained, with an abundance from C. agassizi specimens. All the isolates were taxonomically characterized and were related to different species of Photobacterium, with the exception of Vibrio sp. CLD11 that was from C. agassizi. The luxAB gene was detected in about the 90% of the analysed strains.

The luminescent bacteria inhibition test using Aliivibrio fischeri is a well‐established method to determine the aquatic toxicity of soluble chemicals. More precisely, the effective concentration (EC50) after 15 and 30 min is determined in this test. The inhibition of natural bioluminescence of these bacteria gives a first idea of the toxicity of compounds towards some aquatic organisms. It is a cost and time efficient experimental method, which does not involve animals. In this contribution, the experimental set up, comparability with other measurements, and results of recently described compounds is presented. Different types of energetic materials such as coordination (e. g. [Cu(dtp)3](ClO4)2 and [Fe(MTZ)6](ClO4)2), neutral (e. g. azidoethanol, 1‐ and 2‐aminotetrazole) and ionic (e. g. polynitropyrazolates and PETNC salts) compounds were investigated and compared to commonly used materials, like RDX, ammonium perchlorate (AP) and azide salts. Furthermore, different substitution patterns and energetic functionalities such as azido‐, nitro‐ and nitramino‐groups were investigated. [ABSTRACT FROM AUTHOR]

Developments in industrial applications inevitably accelerate the discharge of enormous substances into the environment, whereas multi-component mixtures commonly cause joint toxicity which is distinct from the simple sum of independent effect. Thus, ecotoxicological assessment, by luminescent bioassays has recently brought increasing attention to overcome the environmental risks. Based on the above viewpoint, this review included a brief introduction to the occurrence and characteristics of toxic bioassay based on the luminescent bacteria. In order to assess the environmental risk of mixtures, a series of models for the prediction of the joint effect of multi-component mixtures have been summarized and discussed in-depth. Among them, Quantitative Structure-Activity Relationship (QSAR) method which was widely applied in silico has been described in detail. Furthermore, the reported potential mechanisms of joint toxicity on the luminescent bacteria were also overviewed, including the Trojan-horse type mechanism, funnel hypothesis, and fishing hypothesis. The future perspectives toward the development and application of toxicity assessment based on luminescent bacteria were proposed.

Although luminescent bacteria-based bioluminescence inhibition assay has been widely used in the toxicity assessment of environmental pollutants, the response of a luminescent bacterium usually lacks specificity to a target analyte. Recently, some specific analyte inductive promoters were fused to the lux genes for the purpose of selective bioluminescent sensing, and suits of specific promoters were fused to lux genes to compose a bioluminescent array sensor for simultaneous identification of multiple analytes. However, specific promoter-based methods still suffer from drawbacks including limited selectivity, slow responding time, expensive to construct different promoters involved plasmids, and laborious to find new promoters. Herein, we proposed a novel strategy to construct a lux reporter array sensor by directly transforming the natural lux genes in different bacterial hosts without the involvement of any specific promoters. Due to the distinct pathways of signal production, the responding time of the current different bacterial host (DBH)-based lux reporter array has nearly an order of magnitude faster than with specific promoter-based methods. The DBH-based lux reporter array was successfully used for simultaneous identification, quantification, and toxicity/bioactivity assessment of multiple metal ions. Obviously, all the chemical synthetic material-based metal ion sensing methods cannot simultaneously achieve analysis and toxicity evaluation. This approach possessed additional advantages of facile construction, easy operation, high selectivity, fast response, and strong adaptability to other analytes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Developments in industrial applications inevitably accelerate the discharge of enormous substances into the environment, whereas multi-component mixtures commonly cause joint toxicity which is distinct from the simple sum of independent effect. Thus, ecotoxicological assessment, by luminescent bioassays has recently brought increasing attention to overcome the environmental risks. Based on the above viewpoint, this review included a brief introduction to the occurrence and characteristics of toxic bioassay based on the luminescent bacteria. In order to assess the environmental risk of mixtures, a series of models for the prediction of the joint effect of multi-component mixtures have been summarized and discussed in-depth. Among them, Quantitative Structure-Activity Relationship (QSAR) method which was widely applied in silico has been described in detail. Furthermore, the reported potential mechanisms of joint toxicity on the luminescent bacteria were also overviewed, including the Trojan-horse type mechanism, funnel hypothesis, and fishing hypothesis. The future perspectives toward the development and application of toxicity assessment based on luminescent bacteria were proposed. [ABSTRACT FROM AUTHOR]

It has been proven that the raw wastewater, secondary effluent and even reclaimed water may have toxic effects on aquatic organisms. In the present study, fractionation procedures combined with bioassays using luminescent bacteria were conducted to identify the fractions that contributed to the acute and long-term toxicity of municipal wastewater. Solid phase extraction was used to divide dissolved organic matter from the wastewater into three fractions, including non-polar, medium-polar and polar fraction. Among these fractions, although the acute toxicity of municipal wastewater was mainly caused by polar and medium-polar chemicals, the acute toxicity induced by the unit mass of the medium-polar fraction was the greatest. Using three kinds of resins, the organic substances in municipal wastewater were classified into six fractions, and the long-term toxicity of these fractions was further identified. The long-term toxicity of the hydrophobic neutrals, which were the primary toxic substances in raw wastewater, decreased after the conventional secondary biological treatment. Hydrophilic neutrals, which accounted for the majority of organic substances in the secondary effluent, were the main substances with long-term toxicity in the secondary effluent. The identification of fractions with acute and long-term toxicity in municipal wastewater is beneficial for further treatment to attenuate the ecotoxicity of wastewater before discharge into the aquatic environment. [ABSTRACT FROM AUTHOR]

Luminescent bacteria-based biosensors are widely used for fast and sensitive monitoring of food safety, water quality, and other environmental pollutions. Recent advancements in biomedical engineering technology have led to improved portability, integration, and intelligence of these biotoxicity assays. Moreover, genetic engineering has played a significant role in the development of recombinant luminescent bacterial biosensors, enhancing both detection accuracy and sensitivity. This review provides an overview of recent advances in the development and applications of novel luminescent bacteria-based biosensors, and future perspectives and challenges in the cutting-edge research, market translation, and practical applications of luminescent bacterial biosensing are discussed., (© 2024 John Wiley & Sons Ltd.)

Toxicity evaluation of wastewater, polluted sediment and water streams is a very crucial aspect of environmental pollution monitoring. In this work, a newly developed luminescent bacterial test using a tropical luminescent bacterium, Photobacterium sp. strain MIE was used to assess the toxicity of several heavy metals using a 15-min assay format. The assessment was carried out by exposing strain MIE to different concentrations of heavy metals ranging from 0.001 to 200 mg/L in a DTX microplate 96 wells. The toxicity result based on the inhibitory concentration (IC50) was Hg (0.053 mg/L) > Ag (0.12 mg/L) > Cu (0.85 mg/L) > Ni (12.32 mg/L) > Zn (18.72 mg/L) > Cr (26.02 mg/L). Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) analyses showed the sensitivity (IC50) of strain MIE to several toxic heavy metals are comparable to the commercial luminescent assay, Microtox™ as both clusters together making it a good choice for an alternative near-real-time monitoring of heavy metals. The sensitivity of strain MIE towards heavy metals was proven through field trial works on several heavy metal-polluted sites in Malaysia. Thus, it is a good candidate as an early detection system for heavy metals in aquatic bodies in tropical countries. [ABSTRACT FROM AUTHOR]

Vibrio fischeri bioluminescence inhibition has been widely used to test acute toxicities of metals and organics contaminants. However, the differences of metals and organics acute toxicities to V. fischeri have not been compared. Here, four heavy metals (Zn2+, Cu2+, Cd2+, Cr6+) and five organics (phenol, benzoic acid, p-hydroxy benzoic acid, nitro-benzene and benzene) acute toxicities to V. fischeri were investigated. Heavy metals toxicities to V. fischeri were increased along with the reaction time, while the organics toxicities kept the same level in different reaction times. In order to explain the difference, the relative cell death rate of V. fischeri was detected. In metals toxicities tests, the bioluminescence inhibition rate of V. fischeri was found to be significantly higher than the relative cell death rate (P

At the beginning of the paper, the level of necessary phenomenology of complex models is discussed. When working with complex systems, which of course include living organisms and ecological systems, it is necessary to use a phenomenological description. An illustration of the phenomenological approach is given, which captures the most significant general principles or patterns of interactions; the specific values of the parameters cannot be calculated from the first principles, but are determined empirically. An appropriate interpretation is also chosen empirically and pragmatically. However, in order to simulate a wider range of situations, it becomes necessary to lower the level of phenomenology, switch to a more detailed description of the system, introducing interaction between selected elements of the system. The requirements for a system model combining ecological, metabolic and genetic levels of cell culture description are formulated. A mathematical model of quorum sensing dynamics during the growth of batch culture of luminescent bacteria at different concentrations of the nutrient substrate has been developed. The model contains four blocks describing ecological, energy, quorum and luminescent aspects of bacterial culture growth. The model demonstrated good agreement with the experimental data obtained. When analyzing the model, three oddities in the behavior of the culture were noted, which presumably can change the idea of some processes taking place during the development of a culture of luminescent bacteria. The results obtained suggest the presence of some additional control system for the luminescent reaction via the synthesis pathways of FMN · Н2 or aliphatic aldehyde. In this case, the generalized description of the contribution of energy metabolism to luminescence only through ATP is too strong a simplification. As a result of comparing the model dynamics with the experiment, a discrepancy arose between the concentration of the substrate (peptone) measured in the experiment and its effective influence on the bacterial population growth. This discrepancy seems to indicate peptone is not the leading substrate, and growth is limited by nutrients contained in the yeast extract, the concentration of which did not change in these experiments. The discrepancies noted between the expectations and the results of experimental data processing, together with the assumptions about the causes of these discrepancies, set the direction for further experimental and theoretical studies of quorum sensing mechanisms in a culture of luminescent bacteria., Competing Interests: The authors declare no conflict of interest., (Copyright © AUTHORS.)

The light emitted by a luminescent bacterium serves as a unique native channel of information regarding the intracellular processes within the individual cell. In the presence of highly sensitive equipment, it is possible to obtain the distribution of bacterial culture cells by the intensity of light emission, which correlates with the amount of luciferase in the cells. When growing on rich media, the luminescence intensity of individual cells of brightly luminous strains of the luminescent bacteria Photobacterium leiognathi and Ph. phosporeum reaches 104-105 quanta/s. The signal of such intensity can be registered using sensitive photometric equipment. All experiments were carried out with bacterial clones (genetically homogeneous populations). A typical dynamics of luminous bacterial cells distributions with respect to intensity of light emission at various stages of batch culture growth in a liquid medium was obtained. To describe experimental distributions, a phenomenological model that links the light of a bacterial cell with the history of events at the molecular level was constructed. The proposed phenomenological model with a minimum number of fitting parameters (1.5) provides a satisfactory description of the complex process of formation of cell distributions by luminescence intensity at different stages of bacterial culture growth. This may be an indication that the structure of the model describes some essential processes of the real system. Since in the process of division all cells go through the stage of release of all regulatory molecules from the DNA molecule, the resulting distributions can be attributed not only to luciferase, but also to other proteins of constitutive (and not only) synthesis., Competing Interests: The authors declare no conflict of interest., (Copyright © AUTHORS.)

The phenolic compounds have posed public concern for potential threats to human health and ecosystem. Tert -butylphenols (TBPs), as one group of emerging contaminants, showed potential endocrine disrupting effects and aquatic toxicities. In the present study, we detected concentrations of 2,4-DTBP ranging from <0.001 to 0.057 μg/L (detection limit: 0.001 μg/L) in drinking water source from the Qiantang River in East China in April 2016. The endocrine disrupting effects of 2-TBP, 2,4-DTBP and 2,6-DTBP toward human estrogen receptor α (ERα), androgen receptor (AR) and thyroid hormone receptor β (TRβ) were evaluated using human recombinant two-hybrid yeast bioassay. Their aquatic toxicities were investigated with indicator organisms including Photobacterium phosphoreum, Vibrio fischeri and freshwater green alga Chlamydomonas reinhardtii. 2-TBP and 2,4-DTBP exhibited moderate antagonistic effects toward human ERα and AR in a concentration-dependent manner. 2-TBP significantly inhibited the light emission of P. phosphoreum . 2-TBP, 2,4-DTBP and 2,6-DTBP significantly inhibited the growth of C. reinhardtii and reduced the chlorophyll content. Our results suggest the potential adverse effects of TBPs on human health and aquatic organisms. The data will facilitate further risk assessment of TBPs and related contaminants. [ABSTRACT FROM AUTHOR]

A novel tool, the DAMTA analyzer (Device for Analytical Monitoring and Toxicity Assessment), designed for fully automated toxicity measurements based on luminescent bacteria as well as for concomitant determination of chemical parameters, was developed and field-tested. The instrument is a robotic water analyzer equipped with a luminometer and a spectrophotometer, integrated on a thermostated reaction plate which contains a movable carousel with 80 cuvettes. Acute toxicity is measured on-line using a wild type Photobacterium phosphoreum strain with measurable bioluminescence and unaltered sensitivity to toxicants lasting up to ten days. The EC50 values of reference compounds tested were consistent with A. fischeri and P. phosphoreum international standards and comparable to previously published data. Concurrently, a laboratory trial demonstrated the feasibility of use of the analyzer for the determination of nutrients and metals in parallel to the toxicity measurements. In a prolonged test, the system was installed only in toxicity mode at the premises of the World Fair “Expo Milano-2015″, a high security site to ensure the quality of the supplied drinking water. The monitoring program lasted for six months during which ca. 2400 toxicity tests were carried out; the results indicated a mean non-toxic outcome of −5.5 ± 6.2%. In order to warrant the system's robustness in detecting toxic substances, Zn was measured daily with highly reproducible inhibition results, 70.8 ± 13.6%. These results assure that this novel toxicity monitor can be used as an early warning system for protection of drinking water sources from emergencies involving low probability/high impact contamination events in source water or treated water. [ABSTRACT FROM AUTHOR]

Tungsten(VI) oxide, WO3, was studied and used as a heterogeneous catalyst for the liquid-phase oxidative abatement and solid-phase decontamination of simulants of chemical warfare agents, CWAs. The catalytic performance of WO3was compared to the one of a soluble W-containing model catalyst, W(IV)-heptaisobutyl polyhedral oligomeric silsesquioxane, W-POSS. In liquid-phase abatement tests, WO3promoted a complete degradation of the toxic agent simulant within 24 h, in the presence of aqueous hydrogen peroxide, at room temperature. In solid-phase decontamination tests, when WO3was mixed with sodium perborate as a solid oxidant, it was also tested in the decontamination of a cotton textile support from organosulfide and organophosphonate agents (simulants of blistering and nerve CWAs, respectively), showing promising performances comparable to, or sometimes better than, a nanostructured TiO2catalyst, taken as a reference material. The environmental impact of the WO3catalyst was assessed on bioluminescentPhotobacterium leiognathiSh1 bacteria, over which no acute nor chronic detrimental effects were recorded. Then, when in contact with a vegetable species such asPhaseolus vulgarisL. (common bean), WO3did not cause damage to the photosynthetic apparatus of the plant, whereas a clear inhibition of the seed germination was evidenced. [ABSTRACT FROM PUBLISHER]

For the 2014 World Cup and the 2016 Olympic Games, Brazil has expanded its airport infrastructure. This will lead to an increase in wastewater generation from aircrafts. This wastewater is traditionally taken from the aircrafts and disposed in the public sewage collection system. However, this residual water may have a different composition than the usual sanitary sewage. Therefore, it is important to study an alternative to treat this kind of wastewater. Thus, the objective of this study was to characterize and analyze the treatment of wastewater from airplane toilets through chemical precipitation for the removal of ammonia in the form of struvite. The airplanes' effluent showed a composition similar to human urine with pH 8.9, ammonia nitrogen 4,215 mg L%1, phosphorus 430 mg LC1 and a very high acute toxicity (Vibrio fischeri). The best treatment for struvite formation was with pH 9.0 and molar ratio Mg:NH4:PO4 equal to 1.5:1.0:1.0. In this case, the removal of ammonia and phosphorus achieved 97.0% and 95.3% respectively. After this procedure, the toxicity by Vibrio fischeri decreased [ABSTRACT FROM AUTHOR]

Drinking water treatment residue (DWTR) seems to be very promising for controlling lake sediment pollution. Logically, acquisition of the potential toxicity of DWTR will be beneficial for its applications. In this study, the toxicity of DWTR and sediments amended with DWTR to Aliivibrio fischeri was evaluated based on the Microtox ® solid and leachate phase assays, in combination with flow cytometry analyses and the kinetic luminescent bacteria test. The results showed that both solid particles and aqueous/organic extracts of DWTR exhibited no toxicity to the bacterial luminescence and growth. The solid particles of DWTR even promoted bacterial luminescence, possibly because DWTR particles could act as a microbial carrier and provide nutrients for bacteria growth. Bacterial toxicity (either luminescence or growth) was observed from the solid phase and aqueous/organic extracts of sediments with or without DWTR addition. Further analysis showed that the solid phase toxicity was determined to be related mainly to the fixation of bacteria to fine particles and/or organic matter, and all of the observed inhibition resulting from aqueous/organic extracts was identified as non-significant. Moreover, DWTR addition not only had no adverse effect on the aqueous/organic extract toxicity of the sediment but also reduced the solid phase toxicity of the sediment. Overall, in practical application, the solid particles, the water-soluble substances transferred to surface water or the organic substances in DWTR had no toxicity or any delayed effect on bacteria in lakes, and DWTR can therefore be considered as a non-hazardous material. [ABSTRACT FROM AUTHOR]

Vibrio fischeri bioluminescence inhibition has been widely used to test acute toxicities of metals and organics contaminants. However, the differences of metals and organics acute toxicities to V. fischeri have not been compared. Here, four heavy metals (Zn2+, Cu2+, Cd2+ and Cr6+) and five organics (phenol, benzoic acid, p-hydroxybenzoic acid, nitro-benzene and benzene) acute toxicities to V. fischeri were investigated. Heavy metals toxicities to V. fischeri were increased along with the reaction time, while the organics toxicities kept the same level in different reaction times. In order to explain the difference, the relative cell death rate of V. fischeri was detected. In metals toxicities tests, the bioluminescence inhibition rate of V. fischeri was found to be significantly higher than the relative cell death rate (P < 0.05), while for the organics toxicities tests, the cell death rate was similar to the bioluminescence inhibition rate. These results indicated that organics acute toxicities to V. fischeri could reflect the death of cell, but metals acute toxicities to V. fischeri may not lead to the death of cell, just represent the bioluminescence inhibition. [ABSTRACT FROM AUTHOR]