Degradation Of Metabolites Research Articles

Effect of zero‐valent iron nanoparticles on the remediation of a clayish soil contaminated with γ‐hexachlorocyclohexane (lindane) in a bioelectrochemical slurry reactor

AbstractIn this research we evaluated the effect of adding zero‐valent iron nanoparticles (ZVI‐NP) to a complete mix bioelectrochemical slurry reactors (BESR) on the remediation of a clayish soil with a high content of organic matter, contaminated with lindane. Five BESR were loaded with a clayish polluted soil (100 mg lindane/kgds), known concentrations of ZVI‐NP, liquid medium, and sulphate‐reducing inoculum to give a 33% w/v soil concentration. A one‐factor experimental design was used, where the effect of nanoparticles concentration [NP] on lindane removal efficiency (ηlin) and other response variables were evaluated. The [NP] levels were 0.0 (background control with electrical connection, BCWC), 2.5 (Exp1), 5.0 (Exp2), and 7.5 gNP/kgds (Exp3). Maximum ηlin (95%) was attained in Exp2 (5 gNP/kgds). Beyond this level the ηlin slightly decreased (Exp3 with 85% ηlin.) Approximately 40%‐57% of lindane was removed in the first 24 hours during a rapid kinetics phase. No metabolites of lindane degradation were detected after 30 days of operation in all the BESR. Energy production increased with [NP]; Exp3 generated 4.3 MJ/tonneds at 30 days, whereas the other treatments produced energy between 1.6 MJ/tonneds‐1.2 MJ/tonneds. Bioelectrical energy could partially offset the requirements of BESR mixing energy. Overall performance evaluation using an ad hoc multicriteria framework indicated that BESR followed the order Exp2 > Exp3 > Exp1 ~ BCWC > ABCWOC (abiotic control without electrical connection). There was a significant, positive effect of the combined BESR and ZVI‐NP technology for the remediation of heavy soils contaminated with lindane.

Mineralization of persistent azo dye pollutants by a microaerophilic tropical lake sediment mixed bacterial consortium

Biological degradation of azo-class industrial dye pollutants is the preferred method of remediation due to its cost effectiveness and environmentally friendly nature. These pollutants however, are known xenobiotics that resist conventional biodegradation methods. The bacterial degradation of azo-class pollutants entails a two-step anaerobic-aerobic sequential process for complete degradation. This study explored the possibility of utilization of a microaerophilic mixed bacterial consortium from tropical lake sediment to conduct a single-step complete mineralization of two azo-class dyes Methyl Orange (MO) and Congo Red (CR). Biodegradation experiments indicated decolourisation, degradation of chemical Oxygen demand (COD), biochemical Oxygen demand (BOD) removal rates in excess of 95% within 50 hours. Degradation metabolite analysis of MO and CR experiments by liquid chromatography-mass spectrometry (LC-MS) indicated that both dyes were catabolised into simpler compounds. Molecular phylogeny of several bacterial isolates from the experiments indicated that individual bacterial isolates possessed MO and CR degradation capability. Findings of this work imply that microaerophilic bacterial populations from tropical lake sediments are capable of rapid mineralisation of complex azo-class pollutants.

In vitro degradation behavior of shape memory PLLA-TMC random copolymers

Poly (lactic acid) (PLA) and poly (trimethylene carbonate) (PTMC) have been in-depth investigated in tissue engineering due to its excellent biocompatibility and controllable biodegradability. However, the acid metabolites of PLA degradation can accelerate the degradation process, resulting in tissue inflammation and postoperative allergy. Here three poly (L-lactide-co-trimethylene carbonate) (PLLA-TMC) random copolymers with L-lactide / 1.3-trimethylene carbonate ratios of 60:40, 70:30, 80:20 (PLTMC64, PLTMC73, PLTMC82 respectively) were synthesized to control the acid degradation and improve the compression resilience. The results showed that LA units on copolymers could improve water uptake and tension strength, reduce weight loss during the degradation (PLTMC82 for 6.53% after 16 weeks in enzymolysis). The crystallization, thermal properties and the surface and section morphology of copolymers were measured in detail for up to 16 weeks. Cell proliferation assay verified that PLLA-TMC copolymers presented excellent biocompatibility. The shape recovered rate of PLTMC73 was the most suitable for surgeons to complete complex implant operation, and 3D bioprinting bone repair scaffolds and 3D structured vascular scaffolds of PLTMC73 both possessed desired shape memory effect. Therefore, PLTMC with appropriate degradation rate and mechanical properties, intrinsically biocompatibility, and excellent shape memory ability, could provide a promising alternative in the field of cardiovascular and bone tissue repair engineering.

Kinetic studies of Congo red dye adsorption by immobilized Aspergillus niger on alginate

Releasing of dye-containing wastewater by the textile industry into general water bodies can adversely affect aquatic ecosystems and human health. The objective of this study is to assess the Congo red dye biodegradation and detoxification by immobilized Aspergillus niger obtained from textile dye wastewater. The effects of process parameters like pH, temperature, reaction time and initial concentration on Congo red degradation were studied. Equilibrium adsorption isotherms, kinetics and thermodynamics were also investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data fitted well to Langmuir isotherm and the kinetic data fitted well to the pseudo-second-order model. The degraded metabolites of Congo red were characterized by using UV–Vis spectrophotometer, Fourier transform infrared spectroscopy and high-performance liquid chromatography, further confirmed that biodegradation of Congo red was due to reduction of the azo bond. Phytotoxicity test confirmed that degradation metabolites were a less toxic than original dye. The reusability of the immobilized Aspergillus niger was repeated with six cycles and removal efficiency ranged from 98 to 72%. The results in this study substantiate that immobilized Aspergillus niger could be employed as a good adsorbent for the removal of Congo red dye from wastewater.

Improved Safety and Anti-Glioblastoma Efficacy of CAT3-Encapsulated SMEDDS through Metabolism Modification.

13a-(S)-3-pivaloyloxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (CAT3) is a novel oral anti-glioma pro-drug with a potent anti-tumor effect against temozolomide-resistant glioma. 13a(S)-3-hydroxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (PF403) is the active in vivo lipase degradation metabolite of CAT3. Both CAT3 and PF403 can penetrate the blood–brain barrier to cause an anti-glioma effect. However, PF403, which is produced in the gastrointestinal tract and plasma, causes significant gastrointestinal side effects, limiting the clinical application of CAT3. The objective of this paper was to propose a metabolism modification for CAT3 using a self-microemulsifying drug delivery system (SMEDDS), in order to reduce the generation of PF403 in the gastrointestinal tract and plasma, as well as increase the bioavailability of CAT3 in vivo and the amount of anti-tumor substances in the brain. Thus, a CAT3-loaded self-microemulsifying drug delivery system (CAT3-SMEDDS) was prepared, and its physicochemical characterization was systematically carried out. Next, the pharmacokinetic parameters of CAT3 and its metabolite in the rats’ plasma and brain were measured. Furthermore, the in vivo anti-glioma effects and safety of CAT3-SMEDDS were evaluated. Finally, Caco-2 cell uptake, MDCK monolayer cellular transfer, and the intestinal lymphatic transport mechanisms of SMEDDS were investigated in vitro and in vivo. Results show that CAT3-SMEDDS was able to form nanoemulsion droplets in artificial gastrointestinal fluid within 1 min, displaying an ideal particle size (15–30 nm), positive charge (5–9 mV), and controlled release behavior. CAT3-SMEDDS increased the membrane permeability of CAT3 by 3.9-fold and promoted intestinal lymphatic transport. Hence, the bioavailability of CAT3 was increased 79% and the level of its metabolite, PF403, was decreased to 49%. Moreover, the concentrations of CAT3 and PF403 were increased 2–6-fold and 1.3–7.2-fold, respectively, in the brain. Therefore, the anti-glioma effect in the orthotopic models was improved with CAT3-SMEDDS compared with CAT3 in 21 days. Additionally, CAT3-SMEDDS reduced the gastrointestinal side effects of CAT3, such as severe diarrhea, necrosis, and edema, and observed less inflammatory cell infiltration in the gastrointestinal tract, compared with the bare CAT3. Our work reveals that, through the metabolism modification effect, SMEDDS can improve the bioavailability of CAT3 and reduce the generation of PF403 in the gastrointestinal tract and plasma. Therefore, it has the potential to increase the anti-glioma effect and reduce the gastrointestinal side effects of CAT3 simultaneously.

Decolorization of acid blue 29, disperse red 1 and congo red by different indigenous fungal strains

Azo dyes are toxic and recalcitrant environmental pollutants in wastewater and soil in many industrial sites in Asia and Arabic countries. The aim of this study was to find fungal species useful in wastewater treatment and soil remediation efforts. We assessed the ability of different indigenous Aspergillus strains (i.e. A. flavus, A. fumigatus, A. niger and A. terreus) to degrade the azo dyes Acid Blue 29 (AB29), Disperse Red 1 (DR1) and Congo Red (CR). The optimal conditions for dye decolorization by the above-mentioned strains appeared to be as follows: temperature range 30–35 °C, pH 7, glucose as the carbon source (10 g/L), ammonium sulphate as the nitrogen source (1.5 g/L) and 100 mg/L initial dye concentration. The Aspergillus strains decolorized all azo dyes more than 86%. The HPLC and GC-MS analyses confirmed that aniline (retention time 9.0 min), 3-nitroaniline (retention time 15.92 min), 4-nitroanline (retention time 17.81 min), N,N’ diethyl-1,4-phenylendiamine (retention time 18.184 min), and benzidine (retention time 15.07 min) were formed as the intermediate metabolites of dye degradation. All Aspergillus strains decolorized 85% of the dyes in synthetic wastewater.

Molecular Characterization of Chlorpyrifos Degrading Bacteria Isolated from Contaminated Dairy Farm Soils in Nakuru County, Kenya

Chlorpyrifos [O, O-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphonothioate] is an organophosphate widely used as an insecticide against a broad spectrum of pests, including as an acaricide against ticks and mites. Due to environmental persistence and toxicity, it should be eliminated quickly from contaminated sites through biodegradation. Microbial bioremediation is one of the most viable ways of removing Chlorpyrifos (CP) from the environment. However, few studies have been conducted on the bacterial diversity that degrades Chlorpyrifos. The enrichment culture technique conducted in this study isolated chlorpyrifos degrading bacteria in soils from dairy farms in Nakuru County, Kenya. The growth response of the bacteria and degradation of Chlorpyrifos was monitored every five days using UV-VIS Spectrophotometer (600nm). Sequential soil and liquid culture enrichments led to the isolation of eighteen (MA1-MA18) bacterial chlorpyrifos degraders with DNA sequences homologous to members of the genera Pseudomonas, Stenotrophomonas, Bacillus, Alicaligenes, and Achromobacter. The efficacy of four (4) strains was further investigated using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The results showed that all four strains significantly degraded Chlorpyrifos in Minimum Salt Medium (MSM), Lysinibacillus sp.HBUM206408 (79.52%), Stenotrophomonas maltophilia (71.43%), Pseudomonas putida (73.32%), and Achromobacter insuavis (71.03%), producing 2-Hydroxy-3,5,6-trichloropyridine (TCP) as a metabolite in MSM as the only source of carbon. Therefore, these strains can be used for the bioremediation of Chlorpyrifos in contaminated soil. There is a need for further studies to determine the possible mechanisms and other metabolites of Chlorpyrifos degradation by the isolates obtained in the study. Besides, future studies should explore the efficacy and survival of the organisms in the contaminated environment.

Toxicity evaluation and biodegradation of phenanthrene by laccase from Trametes polyzona PBURU 12

The newly isolated Trametes polyzona PBURU 12 demonstrated a high tolerance and potential for the degradation of phenanthrene. The fungal isolate was able to tolerate 100ppm of phenanthrene with 45% relative growth. The crude laccase produced by Trametes polyzona PBURU 12 was able to degrade phenanthrene by up to 98% within 24h. The degradation metabolites showed the absence of toxic compounds. Microbial viability tests using E. coli and B. subtilis revealed that the treated phenanthrene was less toxic than untreated phenanthrene. Phytotoxicity and genotoxicity tests, using Vigna radiata and Allium cepa, indicated that the treated phenanthrene was less toxic to the plants. No mutagenic activity was found in the Ames test. The crude laccase from Trametes polyzona PBURU 12 was demonstrated as a potential tool for the biodegradation of PAHs (phenanthrene), with low toxic effects after the degradation.

Stereoselective degradation behavior of the novel chiral antifungal agrochemical penthiopyrad in soil

Penthiopyrad is a chiral carboxamide fungicide with a broad spectrum of fungicidal activity. However, there is no report on the analysis of the enantiomers of penthiopyrad and their environmental behavior. Soil is an important carrier for pesticides to affect the environment. Therefore, this study aimed to investigate the absolute configuration, stereoselective degradation, configuration stability and potential metabolites of this agrochemical in soil under different laboratory conditions. R-(−)-penthiopyrad and S-(+)-penthiopyrad were identified by the electronic circular dichroism method. Regarding the racemic analyte, the degradation half-lives of the stereoisomers ranged from 38.9 to 97.6 days, the S-(+)-stereoisomer degraded preferentially in four types of Chinese soil. However, enantiopure R-(−)-penthiopyrad degraded faster than its antipode, a finding that might be related to the microbial activity in soil. The organic matter (OM) content influenced the stereoselective degradation of rac-penthiopyrad. No configuration conversion was observed in both enantiopure analyte degradation processes. One possible metabolite, 753-A-OH, was detected in the treated soil samples, and the degradation pathway might be a hydroxylation reaction. This is the first report of the absolute configuration of penthiopyrad stereoisomers and the first comprehensive evaluation of the stereoselective degradation of penthiopyrad in Chinese soil. Stereoselective degradation of rac-penthiopyrad was observed in the four types of soil. And the stereoselectivity might be inhibited by OM. This study provides more accurate data to investigate the environmental behavior of penthiopyrad at the stereoisomer level.

Reusability performance of green zinc oxide nanoparticles for photocatalysis of bathroom greywater

Abstract This study aims to investigate the potential of green zinc oxide nanoparticles (ZnO NPs) in reusability performance for photocatalysis of bathroom greywater. It was found that ZnO NPs photocatalytic treatment of real bathroom greywater (RBGW) effluent reduces both the COD and BOD5 concentrations by 72.01, 62.75 and 57.79% (COD) and 70.18, 60.32 and 57.56% (BOD5) respectively for the first, second and third cycle. Meanwhile for the photocatalysis of ABGW, it was observed that COD and BOD5 were removed by 82.27, 68.27 and 60.96% (COD) and 82.91, 74.37 and 60.39% (BOD5) for the first, second and third cycle respectively. Besides, TSS and turbidity were reduced by 52.34, 46.85 and 37.98% (TSS) and 80.38, 67.65 and 56.81% (turbidity) respectively in RBGW and for ABGW, TSS and turbidity were reduced by 60.94, 52.37 and 41.95% (TSS) and 80.68, 72.63 and 69.91% (turbidity) for the first, second and third experimental run respectively. This designates that green ZnO NPs can be reused multiple times as an effective photocatalyst. However, ZnO NPs were used in the dispersed form, which causes difficulty in the separation of ZnO NPs from the greywater. Thus, further investigation in producing appropriate fixed film should be focused. Moreover, phytotoxicity analysis of V. radiate seeds in the treated ABGW and RBGW was not significantly different from their germination in water. This assured the less lethal nature of the degradation metabolites in greywater effluent. This investigation would be a solution to wastewater treatment plant for reusing photocatalyst in order to achieve the development of advanced and greener technologies.

Plasma, Prostate and Urine Levels of Tocopherols and Metabolites in Men after Supplementation with a γ-Tocopherol-Rich Vitamin E Mixture

The vitamin E forms γ- and δ-tocopherols (T) inhibit carcinogenesis in animal models; nevertheless, their cancer preventive activities in humans are uncertain. As an initial step to address this issue, we conducted a pilot phase 0 trial to determine the levels of tocopherols and their metabolites in prostate cancer patients undergoing radical prostatectomy. The patients were randomized to no supplementation or two capsules of a γ-T-rich vitamin E mixture daily for 7 or 14 day prior to prostatectomy. Blood and urine samples were collected before supplementation and on the day of surgery, along with prostate tissue, for analysis of tocopherols and their metabolites. Estimated blood loss during surgery was not significantly different across treatment arms and there were no reported adverse events. Prostate tissue levels of γ-T and δ-T were increased after 14 day of supplementation. Their side-chain degradation metabolites (CEHCs and CMBHCs) were significantly elevated in plasma, prostate and urine samples after supplementation for 7 or 14 day. In conclusion, supplementation with γ-T-rich vitamin E increased the prostate levels of γ-T and δ-T. The use of pure γ-T, δ-T or tocopherol mixtures with higher ratio of γ-T or δ-T to α-T is recommended for future studies.

Microbially mediated cleavage of Reactive Black 5 in attached growth bioreactors with immobilized Shewanella indica strain on different carriers

Decolorization and removal of contaminants in textile wastewater are essential for pollution control. This study investigated the potential application of a halophilic and halotolerant Shewanella indica (S. indica) strain as immobilized biofilm in two attached growth bioreactors with moving bed bioreactor carrier and polyurethane porous gel carrier, respectively. Under optimized operation conditions, both bioreactors had high tolerance for Reactive Black 5 (RB5) concentration fluctuation and could decolorize RB5 effectively and stably (97% on average) for over 6 months. The decolorization of RB5 in bioreactors was mainly due to microbially mediated cleavage of the azo dye, though adsorption by biofilm and carrier (contribution of different carriers varied) also contributed to the process. However, the azo dye was barely mineralized, and the toxicity remained after decolorization. Overall, this study demonstrated the viability and sustainability of the bioreactors incubated with S. indica in decolorizing RB5. Nevertheless, further technologies need to be explored to detoxify the degradation metabolites.

Biodegradation of malachite green by a novel laccase-mimicking multicopper BSA-Cu complex: Performance optimization, intermediates identification and artificial neural network modeling

In this work, a soluble biopolymer was prepared by conjugating the bovine serum albumin (BSA) with transition metal ion (Cu2+). BSA-Cu complex was synthesized and characterized using UV–vis absorption, fluorescence and ATR-FTIR spectroscopies. A colorimetric guaiacol oxidation based method, was used to study the catalytic activity of complex and the results indicated its laccase-like activity. Compared with laccase, BSA-Cu complex showed a higher Km value and a similar Vmax value at the same mass concentration. Also, the ability of the BSA-Cu complex to decolorize malachite green (MG) was tested and the results showed that the complex was able to complete the decolorization process of MG within 30 min. Using gas chromatography/mass spectrometry (GC−MS) the resultant metabolites of MG degradation were analyzed and the toxicity of degradation products was assessed against Escherichia coli and Bacillus subtilis. The results confirmed the formation of less toxic products after degradation of MG by BSA-Cu complex. To predict the decolorization efficiency (DE%) of MG, an artificial neural network (ANN) was designed with five, five and one neurons in the input, hidden and output layers, respectively. The obtained results showed the ability of the designed ANN to predict MG removal successfully.

Pantoprazole niche among the GERD-medicines

Main groups of antisecretory drugs used in the treatment of acid-dependent diseases, including gastroesophageal reflux disease (GERD), are described in a review. Mechanisms of activation, degradation and inactive metabolites formation of proton pump inhibitors (PPIs) – final elements of acid production blockage – are considered in detail. Special attention is paid to the presence of PPIs’ derivatives with different functional activity: inactive derivatives, active and inactive metabolites. Topographic description of these derivatives, their significance in terms of an effect on bioavailability, clinical effectiveness and a potential of PPIs interactions with other administered drugs. The combined decision-making algorithm in the presence of gastroesophageal reflux disease symptoms is presented, compiled on the basis of the most authoritative current recommendations. This algorithm provides for the use of PPIs in standard doses once a day for 4–8 weeks with a possible dose escalation in a case of ineffectiveness. If treatment with high doses of PPIs is ineffective, a set of measures is needed to identify the causes of this inefficiency and to choose additional medical strategy. Depending on the clinical situation, after erosions epithelization the treatment can be stopped, used on demand, prolonged in the intermittent or supportive forms. Particular attention is paid to the Panum® drug, which has proven its effectiveness in patients with different degrees of reflux esophagitis. The availability of dosage forms for prescription and over-the-counter leave allows ensuring its comfortable and unhindered purchase by patients and eliminating excessive burden on the healthcare system.

Mass Spectrometry-Based Discovery of New Chemical Scaffold Rearrangement Ions: Aza-biphenylene as a Novel Potent Biradical Agent in Cancer Chemotherapy.

Discovery of a new drug is time-consuming, laborious, and expensive. Herein, a novel integrative strategy for discovering potential new lead compounds has been developed, which was based on the characteristics of mass spectrometry (MS). MS was used to predict the potential forced degradation products (DPs) and metabolites of drugs by electrospray ionization and collision-induced dissociation (CID). Special rearrangement ions representing unique predicted DPs and metabolites were identified. The consistency between the predicted and the measured results was proven by in vitro metabolism and forced degradation of a commercial drug, respectively. From this, new chemical scaffold rearrangement ions named (aza)-biphenylenes, as potent anticancer agents, were discovered. As a representative aza-biphenylene analogue, 2-azabiphenylene was proven in vitro to induce apoptosis and inhibit the growth of various human cancer cells in a dose-dependent manner. Surprisingly, 2-azabiphenylene exhibited the best comparable bioactivity with the positive control sorafenib, but showed significantly lower in vitro cytotoxicity than sorafenib (at least a 5-fold decrease in cytotoxicity) because it could be targeted to the tumor microenvironment at low pH. A biradical mechanism accompanied by a mitochondrion-dependent oxidative stress mechanism was proposed to explore its anticancer mechanism. The highly reactive intermediate aza-biphenylenediyl worked as an active pharmaceutical ingredient and induced apoptosis of cancer cells. This provided the basis for the potential applications of CID-induced special rearrangement ions in developing new lead compounds.

A review: Roles of carbohydrates in human diseases through regulation of imbalanced intestinal microbiota

• Most of the commercialized prebiotics are produced from functional carbohydrates. • Carbohydrates have beneficial effects on intestinal microbiota community. • Carbohydrates have been applied to treat diseases by regulation of gut microbiota. • Carbohydrates have displayed great potential in promotion of human health. Gut microbiota plays a key role in the maintenance of human health. In most cases, carbohydrates can be fermented by gut microbiota as substrates. By such degradation reaction, the abundances, activities and metabolite production of gut microbiota will be regulated and thus prevent the occurrence of human diseases such as glycolipid metabolism disorders, enteric abnormality, aging and neurodegeneration, cancers and depression. In this paper, we reviewed the roles of carbohydrates in promoting human health through gut microbial regulation, as well as further studies on the regulatory mechanism and potential application of carbohydrates, which need to be strengthened in the future.

Herbicides based on 2,4-D: its behavior in agricultural environments and microbial biodegradation aspects. A review.

One of the main herbicides used in the agricultural environments is 2,4-dichlorophenoxyacetic acid (2,4-D). It is a synthetic plant hormone auxin employed in many crops including rice, wheat, sorghum, sugar cane, and corn to control wide leaf weeds. The indiscriminate use of pesticides can produce numerous damages to the environment. Therefore, this review has the objective to provide an overview on the main characteristics of the herbicides based on 2,4-D, mostly on the role of microorganisms in its degradation and its main degradation metabolite, 2,4- dichlorophenol (2,4-DCP). The remediation processes carried out by microorganisms are advantageous to avoid the pollution of the environment as well as to safeguard the population health.

Surface enhanced Raman scattering of bacteria using capped and uncapped silver nanoparticles.

Surface enhanced Raman scattering (SERS) spectra of bacteria were obtained using citrate (capped) and borohydride (uncapped) generated silver nanoparticles (Ag NPs).The observed differences in SERS spectra are attributed to the manner in which these Ag NPs interact with bacteria. Capped Ag NPs are able to partition through the surface polysaccharides of the bacterial cell to bind to the inner and outer cell membranes, as well as the periplasmic space between them. The resultant spectra show contributions due to the components of the cell envelope and cellular secretions. Uncapped Ag NPs are unable to partition through the polysaccharide outer structures of the cells. Spectral features observed for these uncapped Ag NPs are secretions primarily due to the metabolites of purine degradation.

Qualifying the T-2 Toxin-Degrading Properties of Seven Microbes with Zebrafish Embryo Microinjection Method.

T-2 mycotoxin degradation and detoxification efficiency of seven bacterial strains were investigated with zebrafish microinjection method in three steps ((1) determination of mycotoxin toxicity baseline, (2) examination of bacterial metabolites toxicity, (3) identification of degradation products toxicity). Toxicity of T-2 was used as a baseline of toxic effects, bacterial metabolites of strains as control of bacterial toxicity and degradation products of toxin as control of biodegradation were injected into one-cell stage embryos in the same experiment. The results of in vivo tests were checked and supplemented with UHPLC-MS/MS measurement of T-2 concentration of samples. Results showed that the Rhodococcus erythropolis NI1 strain was the only one of the seven tested (R. gordoniae AK38, R. ruber N361, R. coprophilus N774, R. rhodochrous NI2, R. globerulus N58, Gordonia paraffinivorans NZS14), which was appropriated to criteria all aspects (bacterial and degradation metabolites of strains caused lower toxicity effects than T-2, and strains were able to degrade T-2 mycotoxin). Bacterial and degradation metabolites of the NI1 strain caused slight lethal and sublethal effects on zebrafish embryos at 72- and 120-h postinjection. Results demonstrated that the three-step zebrafish microinjection method is well-suited to the determination and classification of different bacterial strains by their mycotoxin degradation and detoxification efficiency.

Bacterial community composition and function succession under aerobic and anaerobic conditions impacts the biodegradation of 17β-estradiol and its environmental risk

The widespread detection of 17β-estradiol (E2) in the environment has become an emerging concern worldwide due to its endocrine disrupting effects. This work focuses on the aerobic and anaerobic biodegradations of E2 in various sedimentary environments with different availabilities of electron acceptors, including O2, NO3−, Fe3+, SO42−, or HCO3−. The highest removal efficiency (98.9%) and shortest degradation half-life of E2 (t1/2 = 5.0 d) were achieved under aerobic condition, followed by nitrate-reducing, ferric-reducing, sulfate-reducing and methanogenic conditions. We propose four different degradation pathways of E2 based on the metabolites identified under various redox conditions. Although most of E2 was effectively removed under aerobic condition, the potential environmental risk still needs to be considered due to the residual estrogenic activity induced by estrone (E1) formation. The endocrine-disrupting activities, as indicated by estradiol equivalent (EEQ) values, were related to E2 degradation rate and metabolite formation. We further analyzed the succession of bacterial community compositions and functions using Illumina HiSeq sequencing and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). The findings herein evidenced that bacterial community compositions and metabolic functions associated with different redox conditions impact the biodegradation of E2 and its endocrine-disrupting activity. This knowledge will be useful in predicting the environmental fates of estrogenic hormones in various sedimentary environments and aid in establishing appropriate strategies for eliminating potential environmental risks.