Luminescent Bacteria as Bioindicators in Screening and Selection of Enzymes Detoxifying Various Mycotoxins.

Interest in enzymes capable of neutralizing various mycotoxins is quite high. The methods used for the screening and selection of enzymes that catalyze the detoxification of mycotoxins should be sensitive and fast. However toxic compounds can be generated under the action of such enzymes. Thus, the assessment of the overall reduction in the toxic properties of reaction media towards bioluminescent bacteria seems to be the most reasonable control method allowing a quick search for the effective enzymatic biocatalysts. The influence of a wide range of mycotoxins and glucanases, which hydrolyze toxins with different chemical structures, on the analytical characteristics of luminescent photobacteria as a biosensing element has been studied. Different glucanases (ß-glucosidase and endoglucanase) were initially selected for reactions with 10 mycotoxins based on the results of molecular docking which was performed in silico with 20 mycotoxins. Finally, the biorecognizing luminescent cells were used to estimate the residual toxicity of reaction media with mycotoxins after their interaction with enzymes. The notable non-catalytic decrease in toxicity of media containing deoxynivalenol was revealed with luminous cells for both types of tested glucanases, whereas ß-glucosidase provided a significant catalytic detoxification of media with aflatoxin B2 and zearalenone at pH 6.0.

Implication of storage conditions on luminescence response from Photobacterium phosphoreum in free and immobilized form.

Bioluminescent bacteria in the form of a cell suspension for on-site hazard analysis are not suitable as in vivo luminescence in free cells fluctuates and may lead to erroneous results. Furthermore, the culture broth cannot be stored for long durations to continue sensing analytes as the luminescence ceases over time. Factors that affect luminescence response include growth dynamism, and ambient environmental conditions. The present study investigated the effect of storage conditions such as temperature (25 ± 2°C, room temperature; 4°C; and -20°C) and ambient aqueous environment (M1: sucrose, 1.02 M; M2, bioluminescent media [tryptone, 10 g L-1 ; NaCl, 28.5 g L-1 ; MgCl2 .7H2 O, 4.5 g L-1 ; CaCl2 , 0.5 g L-1 ; KCl 0.5 g L-1 ; yeast extract, 1 g L-1 ; H2 O, 1 L]; M3, bioluminescent media and 95% glycerol, 1:1 ratio) on the luminescence emission from the calcium alginate-immobilized Photobacterium phosphoreum (Sb ) against the cells in free suspension for an extended period. The results indicated that both the parameters that were undertaken markedly affected the luminescence. In the study, Sb showed an enhanced luminescence emission than the control up to 18.5-fold and for a prolonged period which can be efficiently utilized for rapid biosensing of hazardous materials.

In vitro Biofilm Formation by Bioluminescent Bacteria Isolated from the Marine Fish Gut.

The internal surface of the animal gastrointestinal tract is covered by microbial biofilms. They play an important role in the development and functioning of the host organism and protect it against pathogens. Microbial communities of gastrointestinal biofilms are less elucidated than luminal microbiota. Therefore, the studies of biofilm formation by gastrointestinal microorganisms are a topical issue. For the first time, we report the formation of a biofilm in vitro by the strains of bioluminescent bacteria isolated from the intestines of marine fish. These bacteria exhibit co-aggregation and tend to attach to solid surfaces. The attachment of cells is accompanied by appearance of the pili. Then, we observed the formation of microcolonies and the production of extracellular polymer substances (EPSs) connecting bacterial cells into an integrated system. The presence of acidic polysaccharides is shown in the EPS when using the ruthenium red staining. Acidic polysaccharides in this matrix is a biochemical evidence of microbial biofilms. On the fibers of the polymer matrix, these bacteria form the "mushroom body"-type structures. Matured biofilms exhibit a specific three-dimensional architecture with pores and channels formed by cells and EPS. We also demonstrated the formation of a biofilm by binary culture of the luminous enterobacterium Kosakonia cowanii and a Gram-positive Macrococcus sp. The data obtained help to understand the role of these bacteria in the intestines of fish. They lead to a new study in the field of investigation of the intestinal microbiome of fish.

An optical detection module-based biosensor using fortified bacterial beads for soil toxicity assessment.

An optical biosensor module for soil contamination assessment is presented, employing bioluminescent bacterial bioreporters encapsulated in poly-dopamine (PD)-coated alginate microbeads. The PD-coated beads displayed improved mechanical strength and stability, but somewhat delayed responses to the inducing toxicant. Using toluene as a model soil contaminant, two bioluminescent reporter strains were employed for its detection in the ambient light-blocking, temperature-controlled biosensor module. Bioluminescence of strain TV1061 (harboring an inducible grpE::luxCDABE fusion) increased and that of strain GC2 (harboring a constitutive lac::luxCDABE fusion) decreased in the presence of increasing toluene concentrations. In the former case, a maximal effect was observed in the presence of 1% toluene. This simple optical detection biosensor module may potentially be utilized for monitoring soil contamination from areas suspected of chemical pollution such petrochemical industrial zones or petrol stations.

Water toxicity evaluations: Comparing genetically modified bioluminescent bacteria and CHO cells as biomonitoring tools.

The use of water for drinking and agriculture requires knowledge of its toxicity. In this study, we compared the use of genetically modified bioluminescent (GMB) bacteria whose luminescence increases in the presence of toxicants and Chinese Hamster Ovary (CHO) cells for the characterization of the toxicity of water samples collected from a lake and streams, hydroponic and aquaponic farms, and a wastewater treatment plant. GMB bacteria were used to probe genotoxicity, cytotoxicity and reactive oxygen species-induced effects in the whole water samples. Unlike GMB bacteria, the use of CHO cells requires XAD resin-based pre-concentration of toxic material present in water samples for the subsequent cytotoxicity assay. In addition to the examination of the toxicity of the water from the different sources, the GMB bacteria were also used to test the XAD extracts diluted to the concentrations causing 50% growth inhibition of the CHO cells. The two biomonitoring tools provided different results when they were used to test the above-mentioned diluted XAD extracts. A pre-concentration procedure based on adsorption by XAD resins with subsequent elution was not sufficient to represent the material responsible for the toxicity of the whole water samples toward the GMB bacteria. Therefore, the use of XAD resin extracts may lead to major underestimates of the toxicity of water samples. Although the toxicity findings obtained using the GMB bacteria and CHO cells may not correlate with each another, the GMB bacteria assay did provide a mechanism-specific biomonitoring tool to probe the toxicity of water samples without a need for the pre-concentration step.

Measuring Artificial Sweeteners Toxicity Using a Bioluminescent Bacterial Panel.

Artificial sweeteners have become increasingly controversial due to their questionable influence on consumers' health. They are introduced in most foods and many consume this added ingredient without their knowledge. Currently, there is still no consensus regarding the health consequences of artificial sweeteners intake as they have not been fully investigated. Consumption of artificial sweeteners has been linked with adverse effects such as cancer, weight gain, metabolic disorders, type-2 diabetes and alteration of gut microbiota activity. Moreover, artificial sweeteners have been identified as emerging environmental pollutants, and can be found in receiving waters, i.e., surface waters, groundwater aquifers and drinking waters. In this study, the relative toxicity of six FDA-approved artificial sweeteners (aspartame, sucralose, saccharine, neotame, advantame and acesulfame potassium-k (ace-k)) and that of ten sport supplements containing these artificial sweeteners, were tested using genetically modified bioluminescent bacteria from E. coli. The bioluminescent bacteria, which luminesce when they detect toxicants, act as a sensing model representative of the complex microbial system. Both induced luminescent signals and bacterial growth were measured. Toxic effects were found when the bacteria were exposed to certain concentrations of the artificial sweeteners. In the bioluminescence activity assay, two toxicity response patterns were observed, namely, the induction and inhibition of the bioluminescent signal. An inhibition response pattern may be observed in the response of sucralose in all the tested strains: TV1061 (MLIC = 1 mg/mL), DPD2544 (MLIC = 50 mg/mL) and DPD2794 (MLIC = 100 mg/mL). It is also observed in neotame in the DPD2544 (MLIC = 2 mg/mL) strain. On the other hand, the induction response pattern may be observed in its response in saccharin in TV1061 (MLIndC = 5 mg/mL) and DPD2794 (MLIndC = 5 mg/mL) strains, aspartame in DPD2794 (MLIndC = 4 mg/mL) strain, and ace-k in DPD2794 (MLIndC = 10 mg/mL) strain. The results of this study may help in understanding the relative toxicity of artificial sweeteners on E. coli, a sensing model representative of the gut bacteria. Furthermore, the tested bioluminescent bacterial panel can potentially be used for detecting artificial sweeteners in the environment, using a specific mode-of-action pattern.

Model of Host-Pathogen Interaction Dynamics Links In Vivo Optical Imaging and Immune Responses.

Tracking disease progression in vivo is essential for the development of treatments against bacterial infection. Optical imaging has become a central tool for in vivo tracking of bacterial population development and therapeutic response. For a precise understanding of in vivo imaging results in terms of disease mechanisms derived from detailed postmortem observations, however, a link between the two is needed. Here, we develop a model that provides that link for the investigation of Citrobacter rodentium infection, a mouse model for enteropathogenic Escherichia coli (EPEC). We connect in vivo disease progression of C57BL/6 mice infected with bioluminescent bacteria, imaged using optical tomography and X-ray computed tomography, to postmortem measurements of colonic immune cell infiltration. We use the model to explore changes to both the host immune response and the bacteria and to evaluate the response to antibiotic treatment. The developed model serves as a novel tool for the identification and development of new therapeutic interventions.

Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant.

BACKGROUND AND OBJECTIVE: The development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers. STUDY DESIGN/MATERIALS AND METHODS: A drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment. RESULTS: Analysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth. CONCLUSIONS: Our results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc.

Screening the toxicity of phosphorous-removal adsorbents using a bioluminescence inhibition test.

When found in excess, phosphorus (P) has been linked to surface water eutrophication. As a result, adsorbents are now used in P remediation efforts. However, possible secondary toxicological impacts on the use of new materials for P removal from surface water have not been reported. This study evaluated the toxicity of adsorbent materials used in the removal of P from surface water including: fly ash, bottom ash, alum sludge, a proprietary mix of adsorbents, and a proprietary engineered material. Toxicity screening was conducted by performing solid-liquid extractions (SLEs) followed by the bacterial bioluminescence inhibition test with a Microtox® M500. Of the materials tested, the samples extracted at lower pH levels demonstrated higher toxicity. The material exhibiting the most toxic response was the iron and aluminum oxide coated engineered material registering a 66-67% 15-min EC50 level for pH 4 and 5 SLEs, respectively. However, for SLEs prepared at pH 7, toxic effects were not detected for this engineered material. Fly ash and bottom ash demonstrated between 82 and 84% 15-min EC50 level, respectively, for pH 4 SLE conditions. Dried alum sludge and the proprietary mix of adsorbents were classified as having little to no toxicity.

Promising Biological Indicator of Heavy Metal Pollution: Bioluminescent Bacterial Strains Isolated and Characterized from Marine Niches of Goa, India.

In present study, several marine water samples collected from the North Goa Beaches, India for isolation of luminescent bacterial species. Isolates obtained labelled as DP1-5 and AB1-6. Molecular characterization including identification of a microbial culture using 16S rRNA gene based molecular technique and phylogenetic analysis confirmed that DP3 & AB1 isolates were Vibrio harveyi. All of the isolates demonstrated multiple metal resistances in terms of growth, with altered luminescence with variable metal concentration. Present investigations were an attempt towards exploring and reporting an updated diversity of bioluminescent bacterial species from various sites around the Goa, India which would be explored in future for constructing luminescence based biosensor for efficiently monitoring the level of hazardous metals in the environment.

Advances in the Development of Bacterial Bioluminescence Imaging.

Bioluminescence imaging (BLI) is a powerful method for visualizing biological processes and tracking cells. Engineered bioluminescent bacteria that utilize luciferase-catalyzed biochemical reactions to generate luminescence have become useful analytical tools for in vitro and in vivo bacterial imaging. Accordingly, this review initially introduces the development of engineered bioluminescent bacteria that use different luciferase-luciferin pairs as analytical tools and their applications for in vivo BLI, including real-time bacterial tracking of infection, probiotic investigation, tumor-targeted therapy, and drug screening. Applications of engineered bioluminescent bacteria as whole-cell biosensors for sensing biological changes in vitro and in vivo are then discussed. Finally, we review the optimizations and future directions of bioluminescent bacteria for imaging. This review aims to provide fundamental insights into bacterial BLI and highlight the potential development of this technique in the future.

Deciphering the growth responses and genotypic diversity of bioluminescent Photobacterium phosphoreum on chicken meat during aerobic refrigerated storage.

The advent of high-throughput sequencing technologies in recent years has revealed the unexpected presence of genus Photobacterium within the chicken meat spoilage ecosystem. This study was undertaken to decipher the occurrence, the growth patterns and the genotypic biodiversity of Photobacterium phosphoreum on chicken breast fillets stored aerobically at 4 °C through conventional microbiological methods and molecular techniques. Samples were periodically cultured on marine broth agar (MA; supplemented with meat extract and vancomycin) for the enumeration of presumptive bioluminescent Photobacterium spp. In total, 90 bioluminescent bacteria were recovered from the initial (time of first appearance), middle and end stages of storage. Concomitantly, 95 total psychrotrophic/psychrophilic bacteria were isolated from the same medium to assess the presence and diversity of non-luminous photobacteria. Genetic diversity between bioluminescent isolates was assessed with two PCR-based DNA fingerprinting methods, i.e. RAPD and rep-PCR. Moreover, the characterization of selected bacterial isolates at the genus and/or species level was performed by sequencing of the 16S rRNA and/or gyrB gene. Bioluminescent bacteria were scarcely encountered in fresh samples at population levels of ca. 2.0 log CFU/g, whilst total psychrotrophic/psychrophilic bacteria were found at levels of ca. 4.4 log CFU/g. As time proceeded and close to shelf-life end, bioluminescent bacteria were encountered at higher populations, and were found at levels of 5.3 and 7.0 log CFU/g in samples from the second and third batch, respectively. In the first batch their presence was occasional and at levels up to 3.9 log CFU/g. Accordingly, total psychrotrophic/psychrophilic bacteria exceeded 8.4 log CFU/g at the end of storage, suggesting the possible underestimation of bioluminescent populations following the specific cultivation conditions. Sequence analysis assigned bioluminescent isolates to Photobacterium phosphoreum, while genetic fingerprinting revealed high intra-species variability. Respectively, total psychrotrophs/psychrophiles were assigned to genera Pseudomonas, Shewanella, Psychrobacter, Acinetobacter, Vibrio and Photobacterium. Non-luminous photobacteria were not identified within the psychrotrophs/psychrophiles. Results of the present study reveal the intra- and inter-batch variability on the occurrence and growth responses of P. phosphoreum and highlight its potential role in the chicken meat spoilage consortium.

Engineering bioluminescent bacteria to boost photodynamic therapy and systemic anti-tumor immunity for synergistic cancer treatment.

The limited penetration depth of external excitation light would remarkably impair the therapeutic efficacy of photodynamic therapy (PDT) and its clinical utilization. Herein, we engineered bioluminescent bacteria by transforming attenuated Salmonella typhimurium strain ΔppGpp (S.T.ΔppGpp) with firefly-luciferase-expressing plasmid (Luc-S.T.ΔppGpp) as an internal light source to evenly illuminate whole tumors. Upon being fixed inside tumors with in-situ formed hydrogel, the colonized Luc-S.T.ΔppGpp together with D-luciferin could continuously generate light to excite photosensitizer chlorin e6 (Ce6), leading to effective suppression of different types of tumors including opaque melanoma and large rabbit tumors. Such bioluminescence-triggered PDT presented significant advantages over conventional PDT excited with an external 660-nm light, which at a much high light energy could only slightly retard the growth of small subcutaneous tumors. Furthermore, we uncovered that Luc-S.T.ΔppGpp boosted PDT could also elicit potent antitumor immunity post the treatment to inhibit tumor metastasis and prevent tumor challenge. Therefore, this work highlights that such bioluminescent bacteria boosted PDT is a general and highly effective therapeutic approach toward diverse cancers with varying light-absorbing capacities and tumor sizes, promising for potential clinical translation because of their acceptable safety profiles.

Restoring phosphorus from water to soil: Using calcined eggshells for P adsorption and subsequent application of the adsorbent as a P fertilizer.

This study investigated the solution for two environmental issues: excess of P in water and its deficiency in soil, which is restored by transferring the adsorbed P from water into the soil using eggshell as an adsorbent. The eggshells were calcined at different temperatures to improve their adsorption capacity, and evaluated for their physical/chemical properties and P adsorption capacity. The eggshells calcined at 800 °C (CES-800) had the highest P adsorption; CaCO3 decomposed into 23.6% of CaO and 40.8% of Ca(OH)2, eluting more Ca that reacted with soluble P in water. X-ray diffraction analysis confirmed that CES-800 removed P as hydroxylapatite by reacting with Ca. Pseudo-first-order and Langmuir models suitably described the kinetic and equilibrium of P adsorption by CES-800, respectively. The maximum adsorption capacity of CES-800 was 108.2 mg g-1. As the solution pH increased from 3 to 11, the adsorption amount decreased from 99.8 mg g-1 to 62.3 mg g-1. The feasibility of CES-800 as a filter medium was assessed using real lake water under dynamic flow conditions; > 90% of P removal was achieved at 158 h, and the P adsorbed was 11.5 mg g-1. When CES-800 and P adsorbed CES-800 (P-CES-800) were applied to the soil at the studied rates, the earthworms were unaffected by toxicity, suggesting the use of both adsorbents in soil without adverse effects. The shoot fresh weight, tiller number, and total dry weight significantly increased in P-CES-800 applied rice plants compared to the control plants, indicating that P-CES-800 can be a good alternative to conventional P-fertilizer in rice cultivation.

Preparation of freeze-dried bioluminescent bacteria and their application in the detection of acute toxicity of bisphenol A and heavy metals.

Current chemical analysis approaches for contaminants have failed to reveal their biotoxicity. Moreover, conventional bioassays are time consuming and exhibit poor repeatability. In this study, we performed the acute toxicity detection of various contaminants (chromium (Cr), cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), tin (Sn), nickel (Ni), and bisphenol A (BPA)) with four bioluminescent bacteria (Vibrio qinghaiensis Q67, V. fischeri, Photobacterium phosphoreum T3, and P. phosphoreum 502) using a rapid, flexible, and low-cost bioassay. We found that the temperature affected the bacterial luminescence, and freeze-dried cells exhibited sensitive toxic responses to contaminants. Indeed, the optimized protectants containing 12% (w/v) trehalose, 4% sucrose, and 2% sorbitol displayed better luminescence and toxic sensitivity. Furthermore, freeze-dried powders of these strains were prepared and subjected to acute toxicity detection. The results showed that all contaminants exhibited acute toxicity toward Q67, but the other strains did not show obvious response to nickel and tin. The relative half-maximal effective concentration (EC50) values of BPA, Cr, Cd, Pb, As, Hg, Ni, and Sn to Q67 were 0.674, 1.313, 11.137, 5.921, 4.674, 0.911, 5.941, and 54.077 mg/L, respectively. In addition, the EC50 values of contaminants toward different strains were suggested to be statistically significant. Freeze-dried Q67 exhibited toxic responses to more contaminants than the other bioluminescent strains; therefore, Q67 was selected to be more suitable than the other strains for single and mixture toxicity detection tests. Compared with other strains, Q67 was more appropriate for the rapid screening of the mixture toxicity of contaminants in samples as a nonspecific screening sensor before the use of standard analysis approaches.

Preclinical confirmation of UVC efficacy in treating infectious keratitis.

PURPOSE: Preclinical evaluation of the therapeutic potential of antimicrobial 265 nm UVC for infectious keratitis. METHODS: Four experiments explored UVC: 1) impact on bacterial and fungal lawns on agar, in individual or mixed culture, 2) bacterial inactivation dose in an in vitro deep corneal infection model, 3) dose validation in an ex vivo porcine keratitis model and 4) efficacy in a masked, randomised, controlled murine keratitis trial using bioluminescent Pseudomonas aeruginosa. RESULTS: Minimum effective UVC exposures ranged between 2 s and 5 s for lawn bacteria and fungi in individual or mixed culture. Significant P. aeruginosa growth inhibition in the in vitro infection model was achieved with 15 s UVC, that resulted in a >3.5 log10 reduction of bacteria in a subsequent ex vivo keratitis model (p < 0.05). Bioluminescence fell below baseline levels in all treated animals, within 8 h of treatment (p < 0.05), in the in vivo study. Re-epithelialisation with corneal clarity occurred within 24 h in 75% of UVC-treated cases, with no relapse at 48 h. On plating, bacteria were recovered only from untreated controls. CONCLUSIONS: UVC inhibited all tested bacteria and fungi, including mixed culture and strains linked to antibiotic resistance, in vitro, with exposures of ≤ 5 s. In vitro and ex vivo testing confirmed therapeutic potential of 15 s UVC. In vivo, 15 s UVC administered in two doses, 4 h apart, proved effective in treating murine bacterial keratitis.

The effect of cannabis toxicity on a model microbiome bacterium epitomized by a panel of bioluminescent E. coli.

The world acceptance of medical cannabis slowly widens. Cannabinoids are known as the main therapeutic active compounds in the cannabis plant, yet their bioactive physiological effects are still unknown. In this study, the mode of action of nine selected cannabinoids was examined using a bioluminescent bacterial panel, as well as the extracts of six different cannabis varieties and cannabinoids standards artificial mixtures. The bacterial panel was composed of genetically modified E. coli bacteria that is commonly found in the gut microbiome, to which a lux operon was added to various stress promoters. The panel was exposed to the cannabinoids in order to identify bacterial defense mechanism, via the aforementioned specific stress types response. This enables the understanding of the toxicity mode of action of cannabinoids. From all the tested cannabinoids, only delta-9-tetrahydrocannabinol (THC) and delta-9-tetrahydrocannabinolic acid A (THCA) produced a genotoxic effect, while the other tested cannabinoids, demonstrated cytotoxic or oxidative damages. Unlike pure cannabinoids, cannabis plant extracts exhibited mostly genotoxicity, with minor cytotoxicity or oxidative stress responses. Moreover, cannabinoids standards artificial mixtures produced a different response patterns compared to their individual effects, which may be due to additional synergistic or antagonistic reactions between the mixed chemicals on the bacterial panel. The results showed that despite the lack of cannabigerol (CBG), cannabidivarin (CBDV), cannabinol (CBN), and cannabichromene (CBC) in the artificial solution mimicking the CN6 cannabis variety, a similar response pattern to the cannabinoids standards mixture was obtained. This work contributes to the understanding of such correlations and may provide a realistic view of cannabinoid effects on the human microbiome.

Large-scale sediment toxicity assessment over the 15,000 km of coastline in the Yellow and Bohai seas, East Asia.

The Yellow and Bohai seas have long been contaminated by persistent toxic substances (PTSs) from numerous (un)known anthropogenic sources. In this study, we used Vibrio fischeri bioassay to evaluate ecotoxicological profiles associated with sedimentary PTSs contamination at a large marine ecosystem (LME) scale. A total of 125 surface sediments collected from the coastal areas of the Yellow and Bohai seas were analyzed both for aqueous and organic extracts. Not surprisingly, the results indicated site-dependent toxicities, but most sites were identified as non-toxic to V. fischeri. For aqueous extracts and organic extracts, 13% and 8% of samples, respectively exhibited marginal toxicity, while 0% and 2% of samples exhibited moderate toxicity. However, it should be noted that organic extracts (mean TU = 56) induced stronger toxicities than aqueous samples (mean TU = 0.4). This result generally back-supported the high toxicity potentials associated with sedimentary sink of organic pollutants. Several PTSs measured in the samples indicated a significant contribution to the observed V. fischeri toxicities. Of note, polycyclic aromatic hydrocarbons (PAHs; r = 0.28, p < 0.05), styrene oligomers (r = 0.41, p < 0.01), and alkylphenols (r = 0.38, p < 0.05) showed significant associations to the observed bacterial inhibition. Among PAHs, benzo[a]anthracene and phenanthrene exhibited a significant contribution to the observed V. fischeri toxicities. Meantime, salinity which reflects the distance from the point sources of land-driven pollutants along the rivers and estuaries in the Yellow and Bohai seas was a key environmental variable representing the sample toxicities. Overall, the present study provides baseline information for evaluating the potential sediment toxicity to implement responsible coastal management at an LME scale, and elsewhere.

Using Cholinesterases and Immobilized Luminescent Photobacteria for the Express-Analysis of Mycotoxins and Estimating the Efficiency of Their Enzymatic Hydrolysis.

Novel sensitive analytical agents that can be used for simple, affordable, and rapid analysis of mycotoxins are urgently needed in scientific practice, especially for the screening of perspective bio-destructors of the toxic contaminants. We compared the characteristics of a rapid quantitative analysis of different mycotoxins (deoxynivalenol, ochratoxin A, patulin, sterigmatocystin, and zearalenone) using acetyl-, butyrylcholinesterases and photobacterial strains of luminescent cells in the current study. The best bioindicators in terms of sensitivity and working range (µg/mL) were determined as follows: Photobacterium sp. 17 cells for analysis of deoxynivalenol (0.8-89) and patulin (0.2-32); Photobacterium sp. 9.2 cells for analysis of ochratoxin A (0.4-72) and zearalenone (0.2-32); acetylcholinesterase for analysis of sterigmatocystin (0.12-219). The cells were found to be more sensitive than enzymes. The assayed strains of photobacterial cells ensured 44%-83% lower limit of detection for deoxynivalenol and sterigmatocystin as compared to the previously known data for immobilized luminescent cells, and the range of working concentrations was extended by a factor of 1.5-3.5. Calibration curves for the quantitative determination of patulin using immobilized photobacteria were presented in this work for the first time. This calibration was applied to estimate the enzyme efficiency for hydrolyzing mycotoxins using zearalenone and His6-tagged organophosphorus hydrolase as examples.

Cell activity evaluation during bacterial bioluminescence oscillation.

Oscillation in bacterial bioluminescence from Photobacterium kishitanii liquid culture was examined regarding reproducibility and bacterial cell activities, i.e., dissolved oxygen (DO) consumption, esterase activity, and product production rate. A frequent increase in DO was suspected to be due to a rapid decrease in luminescence, and a simple model describing not only the monotonous decrease in cell activity, but also the luminescence-DO relationship is proposed.