Development and validation of two analytical strategies for the determination of glucosides of acidic herbicides in cereals and oilseed matrices

The aim of the present research was the development and validation of a selective and reliable method for the indirect and direct determination of acidic herbicide glucosides. Enzymatic deconjugation was investigated as a mild alternative to harsh alkaline hydrolysis. Various enzymatic options for deconjugation were exploited. One out of nine tested specific enzymes proved to be practical and repeatable for different matrices and concentration ranges, leading to the complete deconjugation of the glucosides. The method was validated according to the SANTE/11312/2021 guideline for cereals and oilseeds and for a rice-based infant formula. Additionally, for four acidic herbicide glucosides available on the market, a quantitative method for direct determination of the intact glucosides was optimized and validated. In both methods, the average recoveries were within 70-120%. The limits of quantification (LOQ) achieved were 10 µg kg-1 and 2.5 µg kg-1 for the intact glucosides and the free acids in cereal and oilseeds. For the rice-based infant formula, the LOQ was 1 µg kg-1 (3 µg kg-1 for dichlorprop). To confirm its applicability, the deconjugation approach was tested for fifteen samples (cereals, oilseeds, and citrus) with incurred residues. Comparisons were made between the method without deconjugation, and two methods with deconjugation, the here proposed enzymatic deconjugation and the more commonly used alkaline hydrolysis. The inclusion of enzymatic deconjugation during sample preparation led to an increase up to 2.7-fold compared to analysis without deconjugation. Enzymatic deconjugation resulted in comparable results to alkaline hydrolysis for 13 out of 15 samples.

Comprehensive profiling and semi-quantification of exogenous chemicals in human urine using HRMS-based strategies

Chemicals infiltrate our daily experiences through multiple exposure pathways. Human biomonitoring (HBM) is routinely used to comprehensively understand these chemical interactions. Historically, HBM depended on targeted screening methods limited to a relatively small set of chemicals with triple quadrupole instruments typically. However, recent advances in high-resolution mass spectrometry (HRMS) have facilitated the use of broad-scope target, suspect, and non-target strategies, enhancing chemical exposome characterization within acceptable detection limits. Despite these advancements, establishing robust and efficient sample treatment protocols is still essential for trustworthy broad-range chemical analysis. This study sought to validate a methodology leveraging HRMS-based strategies for accurate profiling of exogenous chemicals and related metabolites in urine samples. We evaluated five extraction protocols, each encompassing various chemical classes, such as pharmaceuticals, plastic additives, personal care products, and pesticides, in terms of their extraction recoveries, linearity, matrix effect, sensitivity, and reproducibility. The most effective protocol was extensively validated and subsequently applied to 10 real human urine samples using wide-scope target analysis encompassing over 2000 chemicals. We successfully identified and semi-quantified a total of 36 chemicals using an ionization efficiency-based model, affirming the methodology's robust performance. Notably, our results dismissed the need for a deconjugation step, a typically labor-intensive and time-consuming process.

Regulation of Atg8 membrane deconjugation by cysteine proteases in the malaria parasite Plasmodium berghei

During macroautophagy, the Atg8 protein is conjugated to phosphatidylethanolamine (PE) in autophagic membranes. In Apicomplexan parasites, two cysteine proteases, Atg4 and ovarian tumor unit (Otu), have been identified to delipidate Atg8 to release this protein from membranes. Here, we investigated the role of cysteine proteases in Atg8 conjugation and deconjugation and found that the Plasmodium parasite consists of both activities. We successfully disrupted the genes individually; however, simultaneously, they were refractory to deletion and essential for parasite survival. Mutants lacking Atg4 and Otu showed normal blood and mosquito stage development. All mice infected with Otu KO sporozoites became patent; however, Atg4 KO sporozoites either failed to establish blood infection or showed delayed patency. Through in vitro and in vivo analysis, we found that Atg4 KO sporozoites invade and normally develop into early liver stages. However, nuclear and organelle differentiation was severely hampered during late stages and failed to mature into hepatic merozoites. We found a higher level of Atg8 in Atg4 KO parasites, and the deconjugation of Atg8 was hampered. We confirmed Otu localization on the apicoplast; however, parasites lacking Otu showed no visible developmental defects. Our data suggest that Atg4 is the primary deconjugating enzyme and that Otu cannot replace its function completely because it cleaves the peptide bond at the N-terminal side of glycine, thereby irreversibly inactivating Atg8 during its recycling. These findings highlight a role for the Atg8 deconjugation pathway in organelle biogenesis and maintenance of the homeostatic cellular balance.

A method for improved detection of 8-isoprostaglandin F2α/β and benzodiazepines in wastewater

Wastewater-based epidemiology is a tool incorporating biomarker analysis that can be used to monitor the health status of a population. Indicators of health include endogenous oxidative stress biomarkers and hormones, or exogenous such as alcohol and nicotine. 8-Iso-prostaglandin F_2α/β is a biomarker of endogenous metabolism that can be used to measure oxidative stress in a community. Benzodiazepines are a harmful subclass of anxiolytics either prescribed or sourced illegally. The analysis of oxidative stress markers and uptake of benzodiazepines in wastewater may provide information about distress in the community. A method has been applied to detect 8-isoPGF_2α/β and the illicit benzodiazepines clonazolam, flubromazolam and flualprazolam in addition to other prescribed benzodiazepines in wastewater. These substances have been sold as counterfeit pharmaceutical products, such as Xanax, which was formulated to include alprazolam. Deconjugation was initially performed on wastewater samples, followed by liquid-liquid extraction for isoprostanes and solid phase extraction for benzodiazepines to determine the total levels of these analytes. Limits of quantification were in the range of 0.5-2 ng/L for all the analytes except 8-isoPGF_2α/β which was 50 ng/L. Stability, recovery and matrix effect studies were also conducted. Finally, this method was applied to influent wastewater from South Australia which showed the prevalence of 8-isoPGF_2α/β and benzodiazepines.

Effective sample preparation procedure for the analysis of free neutral steroids, free steroid acids and sterol sulfates in different tissues by GC-MS

Steroids play an important role in cell regulation and homeostasis. Many diseases like Alzheimer's disease or Smith-Lemli-Opitz syndrome are known to be associated with deviations in the steroid profile. Most published methods only allow the analysis of small subgroups of steroids and cannot give an overview of the total steroid profile. We developed and validated a method that allows the analysis of free neutral steroids, including intermediates of cholesterol biosynthesis, free oxysterols, C₁₉ and C₂₁ steroids, free steroid acids, including bile acids, and sterol sulfates using gas chromatography-mass spectrometry. Samples were analyzed in scan mode for screening purposes and in dynamic multiple reaction monitoring mode for highly sensitive quantitative analysis. The method was validated for mouse brain and liver tissue and consists of sample homogenization, lipid extraction, steroid group separation, deconjugation, derivatization and gas chromatography-mass spectrometry analysis. We applied the method on brain and liver samples of mice (10 months and 3 weeks old) and cultured N2a cells and report the endogenous concentrations of 29 physiological steroids.

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

BACKGROUND

The upper gastrointestinal tract plays a prominent role in human physiology as the primary site for enzymatic digestion and nutrient absorption, immune sampling, and drug uptake. Alterations to the small intestine microbiome have been implicated in various human diseases, such as non-alcoholic steatohepatitis and inflammatory bowel conditions. Yet, the physiological and functional roles of the small intestine microbiota in humans remain poorly characterized because of the complexities associated with its sampling. Rodent models are used extensively in microbiome research and enable the spatial, temporal, compositional, and functional interrogation of the gastrointestinal microbiota and its effects on the host physiology and disease phenotype. Classical, culture-based studies have documented that fecal microbial self-reinoculation (via coprophagy) affects the composition and abundance of microbes in the murine proximal gastrointestinal tract. This pervasive self-reinoculation behavior could be a particularly relevant study factor when investigating small intestine microbiota. Modern microbiome studies either do not take self-reinoculation into account, or assume that approaches such as single housing mice or housing on wire mesh floors eliminate it. These assumptions have not been rigorously tested with modern tools. Here, we used quantitative 16S rRNA gene amplicon sequencing, quantitative microbial functional gene content inference, and metabolomic analyses of bile acids to evaluate the effects of self-reinoculation on microbial loads, composition, and function in the murine upper gastrointestinal tract.

RESULTS

In coprophagic mice, continuous self-exposure to the fecal flora had substantial quantitative and qualitative effects on the upper gastrointestinal microbiome. These differences in microbial abundance and community composition were associated with an altered profile of the small intestine bile acid pool, and, importantly, could not be inferred from analyzing large intestine or stool samples. Overall, the patterns observed in the small intestine of non-coprophagic mice (reduced total microbial load, low abundance of anaerobic microbiota, and bile acids predominantly in the conjugated form) resemble those typically seen in the human small intestine.

CONCLUSIONS

Future studies need to take self-reinoculation into account when using mouse models to evaluate gastrointestinal microbial colonization and function in relation to xenobiotic transformation and pharmacokinetics or in the context of physiological states and diseases linked to small intestine microbiome and to small intestine dysbiosis. Video abstract.

Dose-dependent effects of acetate on the biodegradation of pharmaceuticals in moving bed biofilm reactors

Moving bed biofilm reactors (MBBR) are promising as a post-treatment for removing pharmaceuticals from wastewater. However, the effect of easily degradable carbon sources on the degradation of pharmaceuticals is unclear. This study shows the influence of acetate on the degradation of 26 pharmaceuticals in an MBBR was dose- and compound-dependent: while the degradation of venlafaxine, tramadol and ciprofloxacin was promoted (increase of reaction rate constant (k) by 133%, 212%, 55%) by acetate, its presence caused negative effects on the removal of ibuprofen, citalopram and diclofenac (decrease of k by 76%, 57%, 44%). The deconjugation of acetyl-sulfadiazine was clearly slowed down (decrease of k by 75%) by the dosed acetate, probably due to feedback inhibition by abundant acetate. 17 out of 25 tested compounds were found to be independent of the acetate dosage, which suggested dosing acetate induced minor effects on most of pharmaceuticals' removal. Enrichment of S- or first eluted enantiomer of 4 β-blockers and the metabolite metoprolol acid was observed. Both non-enantioselective (rapid at elevated compound concentration) and enantioselective enzymes (slower and predominant at lower compound concentration) played a part in the biodegradation. High doses of acetate slowed down the enantiomeric enrichment of atenolol, metoprolol, propranolol and metoprolol acid, which demonstrated that the acetate is able to up- or down-regulate enzymes involved in the enantioselective degradation of β-blockers and thus reveals a complex co-metabolism relationship between transformation pathways of pharmaceuticals and carbon source.

Expression, Purification, and Enzymatic Analysis of Plant SUMO Proteases

The conjugation of SUMO can profoundly change the behavior of substrate proteins, impacting a wide variety of cellular responses. SUMO proteases are emerging as key regulators of plant adaptation to its environment because of their instrumental role in the SUMO deconjugation process. Here, we describe how to express, purify, and determine SUMO deconjugation activity of a plant SUMO protease.

Masked mycotoxins: An emerging issue that makes renegotiable what is ordinary

The masked mycotoxins issue is of increasing relevance in the field of food safety. Although under discussion, regulations are still to be set due to the lack of proper toxicological data. In this communication, we discuss the unmet needs to support regulatory bodies in the decision making on this class of compounds.

Deconjugation of soy isoflavone glucuronides needed for estrogenic activity

Soy isoflavones (SIF) are present in the systemic circulation as conjugated forms of which the estrogenic potency is not yet clear. The present study provides evidence that the major SIF glucuronide metabolites in blood, genistein-7-O-glucuronide (GG) and daidzein-7-O-glucuronide (DG), only become estrogenic after deconjugation. The estrogenic potencies of genistein (Ge), daidzein (Da), GG and DG were determined using stably transfected U2OS-ERα, U2OS-ERβ reporter gene cells and proliferation was tested in T47D-ERβ cells mimicking the ERα/ERβ ratio of healthy breast cells and inT47D breast cancer cells. In all assays applied, the estrogenic potency of the aglycones was significantly higher than that of their corresponding glucuronides. UPLC analysis revealed that in U2OS and T47D cells, 0.2-1.6% of the glucuronides were deconjugated to their corresponding aglycones. The resulting aglycone concentrations can account for the estrogenicity observed upon glucuronide exposure. Interestingly, under similar experimental conditions, rat breast tissue S9 fraction was about 30 times more potent in deconjugating these glucuronides than human breast tissue S9 fraction. Our study confirms that SIF glucuronides are not estrogenic as such, and that the small % of deconjugation in the cell is enough to explain the slight bioactivity observed for the SIF-glucuronides. Species differences in deconjugation capacity should be taken into account when basing risk-benefit assessment of these SIF for the human population on animal data.

Sorption and degradation of 17β-estradiol-17-sulfate in sterilized soil-water systems

To identify abiotic processes that govern the fate of a sulfate conjugated estrogen, 17β-estradiol-17-sulfate (E2-17S), soil batch experiments were conducted to investigate the dissipation, sorption, and degradation of radiolabeled E2-17S under sterilized conditions. The aqueous dissipation half-lives (DT50) for E2-17S ranged from 2.5 to 9.3h for the topsoil of high organic carbon (OC) content (1.29%), but E2-17S remained at ∼80% of applied dose in the low OC (0.26%) subsoil by 14 d. The non-linear sorption isotherms indicated limited sorption of E2-17S, and the concentration-dependent log KOC values were 2.20 and 2.45 for the topsoil and subsoil, respectively. Additionally, two types of hydroxyl E2-17S (OH-E2-17S and diOH-E2-17S) were found as major metabolites in the aqueous phase, which represented 9-25% and 6-7% of applied dose for the topsoil and subsoil at 14 d, respectively. Free estrogens, 17β-estradiol (E2) and estrone (E1), were detected from the sorbed phase of the soil-water systems.

Identification of some factors affecting pharmaceutical active compounds (PhACs) removal in real wastewater. Case study of fungal treatment of reverse osmosis concentrate

Many technologies are being developed for the efficient removal of micropollutants from wastewater and, among them, fungal degradation is one of the possible alternative biological treatments. In this article, some factors that might affect pharmaceutically active compounds (PhACs) removal in a fungal treatment of real wastewater were identified in batch bioreactor treating reverse osmosis concentrate (ROC) from urban wastewater treatment plant (WWTP). We found that degradation of PhACs by Trametes versicolor was enhanced by addition of external nutrients (global removal of 44%). Moreover, our results point out that high aeration might be involved in the increase in the concentration of some PhACs. In fact, conjugation and deconjugation processes (among others) affect the removal assessment of emerging contaminants when working with real concentrations in comparison to experiments with spiked samples. Moreover, factors that could affect the quantification of micropollutants at lab-scale experiments were studied.

Isolation of potential probiotic Lactobacillus oris HMI68 from mother's milk with cholesterol-reducing property

The objective of this study was to evaluate the probiotic properties of Lactobacillus strains isolated from mother's milk and their effects on cholesterol assimilation. In this study 120 isolates from mother's milk were phenotypically and genotypically characterized. Among these, only 6 predominant strains were identified as Lactobacillus spp. The following parameters were selected as important test variables in model stomach passage survival trials: acid and bile tolerance, antimicrobial activity, antibiotic susceptibility and cholesterol reduction. Results showed that the considerable variation existed among six strains. Moreover, the strain HMI68 is the most acid-tolerant and the HMI28 and HMI74 is the most acid-sensitive of all strains tested. HMI118 did not grow at 0.5% and 1% bile concentration after 5 h but the HMI68 and HMI43 showed some tolerance to such bile concentration. The differences found in the growth rate were not significant (P > 0.05). HMI68 showed resistance to most of the antibiotics as well as antagonistic activity against the tested pathogens. The amount of cholesterol reduction is increased when the media supplemented with bile salts. HMI68 assimilate 61.05 ± 0.05 μg/ml cholesterol with the presence of 0.3% bile salt this could be significantly decreased by 25.41 ± 1.09 μg/ml without bile salt. HMI68 was identified to be Lactobacillus oris HMI68 and 16S rRNA sequence was deposited in the National Center for Biotechnological Information (GenBank). For the first time the cholesterol-reducing property of L. oris isolated from mother's milk were investigated in this study. Therefore the effective L. oris HMI68 strain was regarded as a candidate probiotic.

Conversion of major soy isoflavone glucosides and aglycones in in vitro intestinal models

SCOPE

This study compares conversion of three major soy isoflavone glucosides and their aglycones in a series of in vitro intestinal models.

METHODS AND RESULTS

In an in vitro human digestion model isoflavone glucosides were not deconjugated, whereas studies in a Caco-2 transwell model confirmed that deconjugation is essential to facilitate transport across the intestinal barrier. Deconjugation was shown upon incubation of the isoflavone glucosides with rat as well as human intestinal S9. In incubations with rat intestinal S9 lactase phlorizin hydrolase, glucocerebrosidase, and cytosolic broad-specific β-glucosidase all contribute significantly to deconjugation, whereas in incubations with human intestinal S9 deconjugation appeared to occur mainly through the activity of broad-specific β-glucosidase. Species differences in glucuronidation and sulfation were limited and generally within an order of magnitude with 7-O-glucuronides being the major metabolites for all three isoflavone aglycones and the glucuronidation during first pass metabolism being more efficient in rats than in humans. Comparison of the catalytic efficiencies reveals that deconjugation is less efficient than conjugation confirming that aglycones are unlikely to enter the systemic circulation.

CONCLUSION

Altogether, the data point at possible differences in the characteristics for intestinal conversion of the major soy isoflavones between rat and human, especially with respect to their deconjugation.

Dissipation and transformation of 17β-estradiol-17-sulfate in soil-water systems

In the environment, estrogen conjugates can be precursors to the endocrine-disrupting free estrogens, 17β-estradiol (E2) and estrone (E1). Compared to other estrogen conjugates, 17β-estradiol-17-sulfate (E2-17S) is detected at relatively high concentrations and frequencies in animal manure and surface runoff from fields receiving manure. To elucidate the lifecycle of manure-borne estrogens and their conjugates in the environment, the fate of radiolabelled E2-17S in agricultural soils was investigated using laboratory batch studies with soils of different organic carbon (OC) content (1.29% for topsoil versus 0.26% for subsoil). E2-17S was found relatively persistent in the aqueous phase throughout the duration of the 14 d experiment. The aqueous E2-17S persisted longer in the subsoil (half-lives (DT₅₀)=64-173 h) than the topsoil (DT₅₀=4.9-26 h), and the aqueous persistence of E2-17S depended on its initial concentration. The major transformation pathway was hydroxylation, yielding mono- and di-hydroxy-E2-17S (OH-E2-17S and diOH-E2-17S). Free estrogens, E2 and E1, were only observed in the sorbed phase of the soil at low concentrations (∼1% of applied dose), which demonstrated that deconjugation and subsequent oxidation had occurred. Although deconjugation was not a major pathway, E2-17S could be a precursor of free estrogens in the environment.