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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]

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]

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]

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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.)

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]

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]

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]

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]

The scientific basis for producing luminescent biosensors containing free and immobilized luminescent bacteria is discussed. Modern technologies for engineering target objects, procedures used to immobilize bacteria in different carriers, as well as procedures for integral and specific biodetection of toxins are presented. Data regarding generation and application of biomonitoring for ecotoxicants derived from natural and genetically engineered photobacterial strains are analyzed. Special attention is given to immobilization of photobacteria in polyvinyl alcohol-containing cryogel. The main physicochemical, biochemical, and technological parameters for stabilizing luminescence in immobilized bacteria are described. Results of the application of immobilized photobacterial preparations both during discrete and continuous biomonitoring for different classes of ecotoxicants are presented. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of dietary and water supplementation of probiotic Streptococcus phocae PI80 on growth, immune response and feed utilization of tiger shrimp Penaeus monodon in earthen ponds. The probiotic bacterium S. phocae PI80 was cultured in large fermenter (50 L) by adding additional carbon source in the form of molasses and glucose along with yeast extract as nitrogen source to enrich S. phocae PI80 biomass. This enriched S. phocae PI80 was administered to shrimp in feed (6.5 × 1013 bacterial cells m L−1) as well as in pond water (5 L/pond). Shrimp growth performance was significantly improved ( P < 0.05) in 120 days culture when the average body weight of treated molasses + yeast extract ( MY) (28.41 ± 0.874 g), glucose + yeast extract ( GY) (27.013 ± 0.698 g) was significantly higher than control (23.63 ± 0.684 g). Food conversion ratio FCR was also found to be reduced significantly in ponds treated with probiotics when compared with control pond (1.89 ± 0.09). Vibrio and luminescent bacteria were found to be lower in the treatment receiving MY group, and we hypothesize that this may lead to greater shrimp survival. Furthermore, fermentation product of S . phocae PI80 added to pond water and feed additives enhanced the shrimp immune system. The results indicated that total haemocytes count ( THC), phenoloxidase ( PO) activity, NBT reductase assay and phagocytic activity significantly increased in shrimps treated with S. phocae PI80. Our study demonstrates that administration of S. phocae PI80 in the water and feed at 6.5 × 1013 colony-forming units (CFU) m L−1 bacterial cells induce immune modulation and enhances the immune ability of P. monodon in pond-reared shrimp and increased the shrimp production. [ABSTRACT FROM AUTHOR]

The simple, useful, rapid, reproducibility and inexpensive luminescent bacteria toxicity test had become the preferred method for acute toxicity testing of water quality. Detection principle of luminescent bacteria toxicity test, common types of luminescent bacteria, and advances in detection technology of luminescent bacteria toxicity test were introduced in this paper. In addition, acute toxicity testing of water quality research status for industrial wastewater, municipal wastewater, drinking water and surface water, and its applications in the monitoring of water pollution rapid response in emergencies of luminescent bacteria toxicity test were also reviewed. The results show that a convenient, rapid and stable online acute water toxicity testing methods and equipments for water quality monitoring, which are developed by full using of the advantages of luminescent bacteria, will be a research focus of luminescent bacteria toxicity test in the future. [ABSTRACT FROM AUTHOR]

The aim of the present study was the chemical characterization of some medically relevant essential oils (tea tree, clove, cinnamon bark, thyme, and eucalyptus) and the investigation of antibacterial effect of the components of these oils by use of a direct bioautographic method. Thin-layer chromatography (TLC) was combined with biological detection in this process. The chemical composition of the oils was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Eucalyptol (84.2%) was the main component of the essential oil of eucalyptus, eugenol (83.7%) of clove oil, and trans-cinnamic aldehyde (73.2%), thymol (49.9%), and terpinen-4-ol (45.8%) of cinnamon bark, thyme and tea tree oils, respectively. Antibacterial activity of the separated components of these oils as well as of their pure main components (eucalyptol, eugenol, trans-cinnamic aldehyde and thymol) was observed against the Gram-negative luminescence gene-tagged plant pathogenic bacterium Pseudomonas syringae pv. maculicola (Psmlux) and the Gram-negative, naturally luminescent marine bacterium Vibrio fischeri. On the whole, the antibacterial activity of the essential oils could be related to their main components, but the minor constituents may be involved in this process. trans-Cinnamic aldehyde and eugenol were the most active compounds in TLC-bioautography. The sensitivity of TLC-bioautographic method can be improved by using luminescent test bacteria. This method is more cost-effective and provides more reliable results in comparison with conventional microbiological methods, e.g., disc-diffusion technique. [ABSTRACT FROM AUTHOR]

The environmental impact of two biocide-free antifouling paints, fluoropolymer and silicone types, painted on a test cylinder was assessed using a battery of ecotoxicity test and chemical analyses for organic micro-pollutants such as perfluoroalkyl substances (PFAS). A biocide paint containing zinc pyrithione (ZnPT2) and cuprous oxide was assessed as a positive control. A standardized laboratory rotating-cylinder method using each test cylinder with artificial seawater was performed for 45 days. After 1 h rotation, the leaked seawater was subjected for bioassay and chemical analyses twice weekly. The seawater extracts from the biocide paint showed adverse effects on bacteria, algae, and crustaceans, but those from the biocide-free paints did not. The leakage seawater from biocide-free paints, after 7-day continuous rotation, contained the same concentration levels of PFAS as blank seawater used to conduct the tests. Thus, no significant toxicities of the biocide-free paints were found under the conditions of this study. Simultaneous analysis of ZnPT2 and copper pyrithione (CuPT2) was developed using an HPLC with a polymeric resin column, showing that ZnPT2 was converted to CuPT2 by trans-chelation in the leakage seawater from the positive control paint. The experimental results using a laboratory rotating-cylinder method demonstrated that biocide-free paints did not markedly affect three species tested and no PFAS was detected. In contrast, biocide paint was significantly toxic to test species and toxicity of the extract on bacteria was partly responsible for CuPT2 produced in leakage seawater. Thus, a laboratory rotating-cylinder method may be applied for ecotoxicological assessment of antifouling paints. [ABSTRACT FROM AUTHOR]

The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDCM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa ( Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40–70% of the cell dry mass weight) were determined. The capacity for synthesizing two-and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates. [ABSTRACT FROM AUTHOR]

The advantages of combined approaches for the evaluation of drinking-water quality, such as effect-directed analysis (EDA) consisting of biological and chemical analytical methods are illustrated in this work by comparing a classical and EDA approach applied to samples from China and Germany. The China samples contain polycyclic aromatic hydrocarbons, alkylanilines, chloroanilines, chloronitrobenzenes, chlorobenzothiazoles, chloroalkylphosphates, as well as pesticides ((4-chloro-2-methylphenoxy)ethanoic acid, metolachlor, atrazine, and the insect repellent N,N-diethyl-3-toluamide) in concentrations between 1 and 1000 µg L-1. The toxicity profiles of two River Elbe samples and one sewage-treatment-plant sample, as determined by the luminescent bacteria test, selectively reflect the contamination background: the first profile only possesses two out of eight fractions well above the significance level of 10% inhibition, in the second profile, all but one fraction lie well above this level, exhibiting also a much higher total toxicity in each fraction as compared with the latter sample. In the third example, all fractions are far above the significance level and show a much higher total toxicity, but also the profile shifts towards less polar fractions. [ABSTRACT FROM AUTHOR]

Manifestation of pleiotropic effects in the isogenic variants of the luminescent bacterium Photobacterium leiognathi 54 was investigated. The decrease or increase of the expression level of bioluminescence was caused by changes in lux operon regulation. The dynamics of the bioluminescence of dark and dim variants did not differ from the dynamics of the initial luminescent variant, but dependence of the level of luminescence intensity on the exogenous autoinducer of the lux operon was revealed. The investigated variants of P. leiognathi 54 inherited fairly stable morphological characteristics, colony architectonics, level of luminescence, and activity of some enzymes; variants with reduced bioluminescence formed colonies of the S type. Stable bright variants with S-and R-type colonies appeared both in the initial strain population and in the dark variant population, but with smaller frequency. Populations of the bright variant with R-type colonies were most heterogeneous; this can be determined by the lack of glucose repression of the bioluminescence in contrast to other investigated inherited variants of P. leiognathi. [ABSTRACT FROM AUTHOR]

Abstract: Although biochemistry and genetics of light emission by cells have been investigated in detail, a biological role for bacterial luminescence has remained obscure for a long time. It was proposed recently that luminescence may stimulate DNA repair, but the specific mechanism of this phenomenon was not investigated. Moreover, experiments showing decreased survival of UV-irradiated lux mutants relative to luminescent cells were performed previously using only one bacterial species, Vibrio harveyi. Here, we demonstrate that dark mutants of various strains of naturally luminescent bacteria (Photobacterium leiognathi, Photobacterium phosphoreum and Vibrio fischeri) are more sensitive to UV irradiation than wild-type cells. Thus, this phenomenon occurs not only in V. harveyi but also in other bacterial species. Using an artificial system of luminescent Escherichia coli in combination with phr mutants (defective in photolyase functions), we found that bacterial luminescence may stimulate photoreactivation, perhaps by providing photons that are necessary for photolyase activity. [Copyright &y& Elsevier]

Hydrophobic organic pollutants in water from the Huaihe River were extracted by solid phase extraction and sequestered by semipermeable membrane device (SPMD), and those in sediments were extracted by organic solvent. Combined with chemical analysis, Lumistox test and ethoxyresorfin O-deethylase (EROD) assay were carried out for assessing the acute toxicities and the Ah-receptor-related toxic effects of the trace hydrophobic organic pollutants in this aquatic environment. The acute toxicants in water and sediment of the Huaihe River included substituted benzenes and pesticides, mainly 2,4,6-trichlorophenol, atrazine, hexachlorobenzene, and nitrobenzenes as well as persistent EROD inducers or Ah-agonists, including PAHs and PCBs, were determined. The highest acute toxicant concentration occurred at the center of the river (H3), while highest chronic toxicants occurred at upstream (H1). At downstream (H4), the EROD inducers in sediment depicted more persistency. The results also showed that the sampling procedures for waters have significant influences on the results of bioassays. Bioassay for acute toxicants in water using SPE was unable to obtain important information. However, bioassays for sediment extracts and SPMD concentrates showed similar pattern of toxic variation among different locations. [ABSTRACT FROM AUTHOR]

Five municipal sewers with small flow rates (Manarola, Riomaggiore, Portovenere, Tellaro, Bocca di Magra) were studied using the Microtox &circledR; test and a bacterial luminescence bioassay in order to evaluate the water quality in these areas of the eastern Ligurian coast. The work was performed including chemical analysis, microbiological and ecotoxicological assays. Analyses were carried out on both the effluents and the water body close to the pipe discharge. None of the measured chemical parameters exceeded the permitted limits, both in the effluents and in the seawater samples, even if some slightly critical situations were highlighted by the Microtox &circledR; test on the effluents. On the other hand, the Microtox &circledR; appeared to be less effective than another ecotoxicological assay based on the luminescent fraction of epibacteria for the evaluation of seawater quality. The good water quality of the considered areas was assessed although a slightly worse condition was encountered in Bocca di Magra. [ABSTRACT FROM AUTHOR]

The process of leaf senescence is biochemically characterized by the transition from nutrient assimilation to nutrient remobilization. The nutrient drain by developing vegetative and reproductive structures has been implicated in senescence induction. The steady-state levels of amino acids in senescing leaves are dependent on the rate of their release during protein degradation and on the rate of efflux into growing structures. To determine the possible regulatory role of amino acid content in leaf senescence, an in planta non-destructive, semi-quantitative method for the analysis of endogenous levels of free amino acids has been developed. The method is based on in vivo bioluminescence of amino acid-requiring strains of recombinant Escherichia coli carrying the lux gene. The luminescence signal was found to be proportional to the levels of added exogenous tryptophan and to the free amino acid levels in the plant tissues analysed. During the senescence of tobacco flowers and of detached leaves of oats and Arabidopsis, a progressive increase in the levels of free amino acids was monitored. By contrast to the detached leaves, the attached oat leaves displayed a decrease in the levels of free amino acids during senescence. In Arabidopsis, both the attached and detached leaves exhibited a similar pattern of gradual increase in amino acid content during senescence. The differences between the sink–source balance of the two species and the possible relationships between amino acid content and leaf senescence are discussed. [ABSTRACT FROM PUBLISHER]

De-icers are essential to wintertime road maintenance in Nordic countries. The use of road salts (NaCl, CaCl2 and MgCl2) is having significant effects on groundwater. There has been a growing concern of environmental effects resulting from de-icing. Regulatory bodies have tried to find de-icers which have less harmful impacts on soil and groundwater. Alternative new organic de-icers are e.g. potassium formiate, potassium acetate, and calcium magnesium acetate. At present, the decision finding for soil and water quality assessment is mainly based on the results of chemical analyses. However, ecotoxicological characterization will provide more useful information for determining environmental effects of de-icers. Six different de-icers, NaCl, CaCl2, MgCl2, potassium formicate KFo, potassium acetate KAc and calcium magnesium acetate CMA were studied with different bioassays. These bioassays were two plant tests (onion Allium cepa root elongation test and duckweed Lemna growth inhibition test), an enzyme inhibition test (reverse electron transport test, RET) and a microbial test (luminescent bacteria Vibrio fischeri, BioTox test). Most of the responses of the de-icers tested were toxic to test organisms. CMA was unsuitable for RET and BioTox tests because it was not possible to analyze turbid samples with these bioassays. On the whole, organic chemicals were more toxic than the inorganic salts. According to the Lemna and Allium cepa tests KFo was the most toxic and the toxicity ranking of the de-icers was KFo > KAc > CMA > CaCl2 > NaCl > MgCl2. The sensitivity ranking for tests in decreasing order was Lemna > Allium cepa > RET > BioTox. The plant tests proved to be relevant, easy, cost-effective and sensitive screening methods of de-icers: Lemna test was 92 times more sensitive and Allium test 70 times more sensitive than BioTox to KFo. The tested de-icers had significant effects on plant growth, microbial luminescence and enzymatic activity. Toxicity could hardly be predicted from the chemical concentrations of these de-icers. In summary, these results demonstrate a need for including toxicity measurements in the evaluation of technologies used in soil treatment and illustrate the potential value of such measurements for ensuring that no or minimal environmental contamination would arise from de-icing process. [ABSTRACT FROM AUTHOR]

Copyright of Umweltwissenschaften und Schadstoff-Forschung is the property of Springer Nature 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.)

The activated sludge respiration inhibition test and the luminescent bacteria test with Vibrio fischeri are important bacterial test systems for evaluation of the toxicity of chemical compounds. These test systems were further optimized to result in better handling, reliability and sensitivity. Concerning the Vibrio fischeri test, media components such as yeast extract and bivalent cation concentrations like Ca2+ and Mg2+ were optimized. The cultivation, storage conditions and reactivation process of the stored bacteria were also improved, which enabled simpler handling and led to good reproducibility. Additionally, the respiration inhibition test with a prolonged incubation time was further analyzed using different chlorinated phenols as reference compounds. It could be stated that a longer incubation period significantly improved the sensitivity of the test system. [ABSTRACT FROM AUTHOR]

This paper presents the statistical analysis of the results of an inter-laboratory study for the luminescent bacteria toxicity bioassay. It also contains a discussion on the statistical methods for the presentation and refinement of the evaluation of the precision of an assay method (including intra- and inter-laboratory variability), with special emphasis on the rejection of outliers, and the use of standardized parameters, like the repeatability and reproducibility values. [ABSTRACT FROM AUTHOR]