Fast and sustainable planar yeast-based bioassay for endocrine disruptors in complex mixtures: Start of cell cultivation to result within one day

High-performance thin-layer chromatography hyphenated with planar multiplex bioassays and high-resolution tandem mass spectrometry contributes to the non-target detection or even identification of active compounds in complex mixtures such as food, feed, cosmetics, commodities, and environmental samples. It can be used to discover previously unknown harmful or active substances in complex samples and to tentatively assign molecular formulas. This method is already faster than the commonly used in vitro assays along with liquid chromatographic separations, but overnight cell cultivation still prevents a planar bioassay from being performed within one day. There is also still potential for optimization in terms of sustainability. To achieve this, the planar bioassay protocols for the detection of androgen-like and estrogen-like compounds were harmonized. The successful minimization of the cell culture volume enabled accelerated cell cultivation, which allowed the bioassay to be performed within one day. This was considered a milestone achieved, as up to 23 samples per plate can now be analyzed from the start of cultivation to the biological endpoint on the same day. Doubling the substrate amount and increasing the pH of the silica gel layer led to a more sensitive and selective bioassay due to the enhanced fluorescence of the formed end-product. The faster and more sustainable bioassay protocol was applied to complex samples such as sunscreen and red wine to detect estrogen-like compounds. The developed method was validated by comparison with a standard method.

High-throughput characterization of bacterial responses to complex mixtures of chemical pollutants

Our understanding of how microbes respond to micropollutants, such as pesticides, is almost wholly based on single-species responses to individual chemicals. However, in natural environments, microbes experience multiple pollutants simultaneously. Here we perform a matrix of multi-stressor experiments by assaying the growth of model and non-model strains of bacteria in all 255 combinations of 8 chemical stressors (antibiotics, herbicides, fungicides and pesticides). We found that bacterial strains responded in different ways to stressor mixtures, which could not be predicted simply from their phylogenetic relatedness. Increasingly complex chemical mixtures were both more likely to negatively impact bacterial growth in monoculture and more likely to reveal net interactive effects. A mixed co-culture of strains proved more resilient to increasingly complex mixtures and revealed fewer interactions in the growth response. These results show predictability in microbial population responses to chemical stressors and could increase the utility of next-generation eco-toxicological assays.

In silico and in vitro assays suggests Congo red dye degradation by a Lentinus sp. laccase enzyme

Laccase is a superfamily of ligninolytic enzymes known to degrade a wide variety of xenobiotics, including synthetic dyes. Congo Red (CR) has a diazo dye function, carcinogenic and mutagenic potential, and is currently applied in clinical analysis. The objective of this work was to produce and characterize the crude extract of Lentinus sp. in semi-solid fermentation (FSS) and perform in vitro and in silico studies to assess the potential of the crude extract to discolor the CR dye. Laccase activity was determined using ABTS as substrate and characterized. The in vitro discoloration was carried out using experimental design 22 at room temperature and monitored at 340 nm for 24h. Molecular docking and molecular dynamics simulations were performed between laccase and CR. The maximum laccase activity production was 29.63 U L-1 with six days of FSS. The optimal temperature and pH were 50 °C and 3.0, respectively. Discoloration of the CR dye was obtained only in tests containing CuSO4. Laccase formed stable complexes with the dye, presenting negative binding energy values ranging from -70.94 to -63.16 kcal mol-1 and the occurrence of seven hydrogen bonds. Molecular dynamics results showed the stability of the system (RMSD ranging from 1.0 to 2.5 Ä) and protein-ligand interaction along simulation. RMSF values pointed residues at the end of chains A (residues 300 to 305, 480 to 500) and B (residues 650 to 655 and 950 to 1000) as the most flexible regions of the laccase. This study highlighted the enzymatic action in the bioremediation of CR in vitro in agreement with the in silico simulations that demonstrate the enzyme potential.Communicated by Ramaswamy H. Sarma.

A simple 1H (12C/13C) filtered experiment to quantify and trace isotope enrichment in complex environmental and biological samples

Nuclear magnetic resonance (NMR) based 13C tracing has broad applications across medical and environmental research. As many biological and environmental samples are heterogeneous, they experience considerable spectral overlap and relatively low signal. Here a 1D 1H-12C/13C is introduced that uses "in-phase/opposite-phase" encoding to simultaneously detect and discriminate both protons attached to 12C and 13C at full 1H sensitivity in every scan. Unlike traditional approaches that focus on the 12C/13C satellite ratios in a 1H spectrum, this approach creates separate sub-spectra for the 12C and 13C bound protons. These spectra can be used for both quantitative and qualitative analysis of complex samples with significant spectral overlap. Due to the presence of the 13C dipole, faster relaxation of the 1H-13C pairs results in slight underestimation compared to the 1H-12C pairs. However, this is easily compensated for, by collecting an additional reference spectrum, from which the absolute percentage of 13C can be calculated by difference. When combined with the result, 12C and 13C percent enrichment in both 1H-12C and 1H-13C fractions are obtained. As the approach uses isotope filtered 1H NMR for detection, it retains nearly the same sensitivity as a standard 1H spectrum. Here, a proof-of-concept is performed using simple mixtures of 12C and 13C glucose, followed by suspended algal cells with varying 12C /13C ratios representing a complex mixture. The results consistently return 12C/13C ratios that deviate less than 1 % on average from the expected. Finally, the sequence was used to monitor and quantify 13C% enrichment in Daphnia magna neonates which were fed a 13C diet over 1 week. The approach helped reveal how the organisms utilized the 12C lipids they are born with vs. the 13C lipids they assimilate from their diet during growth. Given the experiments simplicity, versatility, and sensitivity, we anticipate it should find broad application in a wide range of tracer studies, such as fluxomics, with applications spanning various disciplines.

Electrocatalytic denitrification biofilter for advanced purification of chlorophenols via ceramsite-based Ti/SnO2-Sb particle electrode: Performance, microbial community structure and mechanism

In response to the demand for advanced purification of industrial secondary effluent, a new method has been developed for treating chlorophenol wastewater using the novel ceramsite-based Ti/SnO2-Sb particle electrodes (Ti/SnO2-Sb/CB) enhanced electrocatalytic denitrification biofilter (EDNBF-P) to achieve removal of chlorophenols (CPs), denitrification, and reduction of effluent toxicity. The results showed that significantly improved CPs and TN removal efficiency at low COD/N compared to conventional denitrification biofilter, with CPs removal rates increasing by 0.33%-59.27% and TN removal rates increasing by 12.53%-38.92%. Under the conditions of HRT = 2h, 3V voltage, charging times = 12h, and 25 °C, the concentrations of the CPs in the effluent of EDNBF-P were all below 1 mg/L, the TN concentration was below 15 mg/L, while the effluent toxicity reached the low toxicity level. Additionally, the Ti/SnO2-Sb/CB particle electrodes effectively alleviated the accumulation of NO2--N caused by applied voltage. The Silanimonas, Pseudomonas and Rhodobacter was identified as the core microorganism for denitrification and toxicity reduction. This study validated that EDNBF-P could achieve synergistic treatment of CPs and TN through electrocatalysis and microbial degradation, providing a methodological support for achieving advanced purification of chlorophenol wastewater with low COD/N in industrial applications.

Molecular docking, molecular dynamics simulations and binding free energy studies of interactions between Mycobacterium tuberculosis Pks13, PknG and bioactive constituents of extremophilic bacteria

Mycobacterial pathogens present a significant challenge to disease control efforts globally due to their inherent resistance to multiple antibiotics. The rise of drug-resistant strains of Mycobacterium tuberculosis has prompted an urgent need for innovative therapeutic solutions. One promising way to discover new tuberculosis drugs is by utilizing natural products from the vast biochemical space. Multidisciplinary methods can used to harness the bioactivity of these natural products. This study aimed to evaluate the antimycobacterial efficacy of functional crude extracts from bacteria isolated from gold mine tailings in South Africa. Bacterial strains were identified using 16S rRNA sequencing. The crude extracts obtained from the bacteria were tested against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. Untargeted HPLC-qTOF and molecular networking were used to identify the functional constituents present in extracts that exhibited inhibitory activity. A virtual screening workflow (VSW) was used to filter compounds that were strong binders to Mycobacterium tuberculosis Pks13 and PknG. The ligands returned from the VSW were subjected to optimization using density functional theory (DFT) at M06-2X/6-311++ (d,p) level of theory and basis set implemented in Gaussian16 Rev.C01. The optimized ligands were re-docked against Mycobacterium tuberculosis Pks13 and PknG. Molecular dynamics simulation and molecular mechanics generalized born surface area were used to evaluate the stability of the protein-ligand complexes formed by the identified hits. The hit that showed promising binding characteristics was virtually modified through multiple synthetic routes using reaction-driven enumeration. Three bacterial isolates showed significant activity against the two strains of Mycobacterium, while only two, Bacillus subtilis and Bacillus licheniformis, exhibited activity against both Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. The tentatively identified compounds from the bacterial crude extracts belonged to various classes of natural compounds associated with antimicrobial activity. Two compounds, cyclo-(L-Pro-4-OH-L-Leu) and vazabitide A, showed strong binding against PknG and Pks13, with pre-MD MM-GBSA values of - 42.8 kcal/mol and - 47.6 kcal/mol, respectively. The DFT-optimized compounds exhibited the same docking scores as the ligands optimized using the OPSL-4 force field. After modifying vazabitide A, its affinity to the Pks13 binding site increased to - 85.8 kcal/mol, as revealed by the post-MD MM-GBSA analysis. This study highlights the potential of bacteria isolates from gold mine tailings as a source of new scaffolds for designing and optimizing anti-Mycobacterium agents. These agents synthesized in-silico can be further tested in-vitro to evaluate their efficacy.

Hazard assessment of complex legacy-contaminated groundwater mixtures using a novel approach method in adult fathead minnows

Traditional risk assessment methods face challenges in the determination of drivers of toxicity for complex mixtures such as those present at legacy-contaminated sites. Bioassay-driven analysis across several levels of biological organization represents an approach to address these obstacles. This study aimed to apply a novel transcriptomics tool, the EcoToxChip, to characterize the effects of complex mixtures of contaminants in adult fathead minnows (FHMs) and to compare molecular response patterns to higher-level biological responses. Adult FHMs were exposed for 4 and 21 days to groundwater mixtures collected from a legacy-contaminated site. Adult FHM showed significant induction of micronuclei in erythrocytes, decrease in reproductive capacities, and some abnormal appearance of liver histology. Parallel EcoToxChip analyses showed a high proportion of upregulated genes and a few downregulated genes characteristic of compensatory responses. The three most enriched pathways included thyroid endocrine processes, transcription and translation cellular processes, and xenobiotics and reactive oxygen species metabolism. Several of the most differentially regulated genes involved in these biological pathways could be linked to the apical outcomes observed in FHMs. We concluded that molecular responses as determined by EcoToxChip analysis show promise for informing of apical outcomes and could support risk assessments of complex contaminated sites.

Predictive value of the ToxCast/Tox21 high throughput toxicity screening data for approximating in vivo ecotoxicity endpoints and ecotoxicological risk in eco- surveillance applications

Ecotoxicology has long relied on assessing the hazard potential of chemicals through traditional in vivo testing methods to understand the possible risk exposure could pose to ecological taxa. In the past decade, the development of non-animal new approach methods (NAMs) for assessing chemical hazard and risk has quickly grown. These methods are often cheaper and faster than traditional toxicity testing, and thus are amenable to high-throughput toxicity testing (HTT), resulting in large datasets. The ToxCast/Tox21 HTT programs have produced in vitro data for thousands of chemicals covering a large space of biological activity. The relevance of these data to in vivo mammalian toxicity has been much explored. Interest has also grown in using these data to evaluate the risk of environmental exposures to taxa of ecological importance such as fish, aquatic invertebrates, etc.; particularly for the purpose of estimating the risk of exposure from real-world complex mixtures. Understanding the relationship and relative sensitivity of NAMs versus standardized ecotoxicological whole organism models is a key component of performing reliable read-across from mammalian in vitro data to ecotoxicological in vivo data. In this work, we explore the relationship between in vivo ecotoxicity data from several publicly available databases and the ToxCast/Tox21 data. We also performed several case studies in which we compare how using different ecotoxicity datasets, whether traditional or ToxCast-based, affects risk conclusions based on exposure to complex mixtures derived from existing large-scale chemical monitoring data. Generally, predictive value of ToxCast data for traditional in vivo endpoints (EPs) was poor (r ≤ 0.3). Risk conclusions, including identification of different chemical risk drivers and prioritized monitoring sites, were different when using HTT data vs. traditional in vivo data.

High efficiency of drinking water treatment residual-based sintered ceramsite in biofilter for domestic wastewater treatment

Aluminum (Al)-based drinking water treatment residue (DWTR) has often been attempted to be recycled as dominant ingredient to produce sintered ceramsite for water treatment. This study aimed to determine the long-term performance of DWTR-based ceramsite in treating domestic wastewater based on a 385-d biofilter test and by using physicochemical, metagenomic, and metatranscriptomic analyses. The results showed that the ceramsite-packed biofilter exhibited high and stable capability in removing phosphorus (P) and chemical oxygen demand (COD), with removal efficiencies of 92.6 ± 3.97% and 81.1 ± 14.0% for total P and COD, respectively; moreover, 88-100% of ammonium-nitrogen (N) was normally converted, and the total N removal efficiency reached 80-86% under proper aeration. Further analysis suggested that the forms of the removed P in the ceramsite were mainly NH4F- and NaOH-extractable. Microbial communities in the ceramsite biofilter exhibited relatively high activity. Typically, various organic matter degradation-related genes (e.g., hemicellulose and starch degradations) were enriched, and a complete N-cycling pathway was established, which is beneficial for enriching microbes involved in ammonium-N conversion, especially Candidatus Brocadia, Candidatus Jettenia, Nitrosomonas, and Nitrospira. In addition, the structures of the ceramsite had high stability (e.g., compressive strength and major compositions). The ceramsites showed limited metal and metalloid pollution risks and even accumulated copper from the wastewater. These results demonstrate the high feasibility of applying ceramsite prepared from Al-based DWTR for water treatment.

Club cell protein (CC16) in serum as an effect marker for small airway epithelial damage caused by diesel exhaust and blasting fumes in potash mining

OBJECTIVE

The effect marker club cell protein (CC16) is secreted by the epithelium of the small respiratory tract into its lumen and passes into the blood. Increased amounts of CC16 in serum are observed during acute epithelial lung injury due to air pollutants. CC16 in serum was determined as part of this cross-sectional study in underground potash miners on acute and chronic health effects from exposures to diesel exhaust and blasting fumes.

METHODS

Nitrogen oxides, carbon monoxide, and diesel particulate matter were measured in 672 workers at a German potash mining site on a person-by-person basis over an early shift or midday shift, together with CC16 serum concentrations before and after the respective shift. CC16 concentrations and CC16 shift-differences were evaluated with respect to personal exposure measurements and other quantitative variables by Spearman rank correlation coefficients. CC16 shift-differences were modeled using multiple linear regression. Above-ground workers as reference group were compared to the exposed underground workers.

RESULTS

Serum concentrations of CC16 were influenced by personal characteristics such as age, smoking status, and renal function. Moreover, they showed a circadian rhythm. While no statistically significant effects of work-related exposure on CC16 concentrations were seen in never smokers, such effects were evident in current smokers.

CONCLUSION

The small airways of current smokers appeared to be vulnerable to the combination of measured work-related exposures and individual exposure to smoking. Therefore, as health protection of smokers exposed to diesel exhaust and blasting fumes, smoking cessation is strongly recommended.

Unveiling the Antimicrobial and Larvicidal Potential of Butyrolactones and Orsellinic Acid Derivatives from the Morus alba-derived Fungus Aspergillus terreus via Integrated In vitro and In silico Approaches

The emergence of multi-drug-resistant microbial strains spurred the search for antimicrobial agents; as a result, two distinct approaches were combined: four in vitro studies and four corresponding molecular docking investigations. Antituberculosis, anti-methicillin-resistant Staphylococcus aureus (anti-MRSA), antifungal, and larvicidal activities of the crude extract, two fractions, and seven isolated compounds from Aspergillus terreus derived from Morus alba roots were explored. The isolated compounds (5 butyrolactones and 2 orsellinic acid derivatives) showed potent to moderate antitubercular activity with MIC values ranging from 1.95 to 62.5 μg/mL (compared to isoniazid, 0.24 μg/mL) and promising anti-MRSA potential with inhibition zone diameters ranging from 8 to 25 mm. Additionally, the in silico study proved that the isolated compounds bind to the two corresponding proteins' active sites with high to moderate -(C-Docker interaction energies) and stable interactions. The isolated compounds displayed antifungal activities against different fungal strains at diverse degrees of activity, among them compound (8"S,9")-dihydroxy-dihydrobutyrolactone I eliciting the best antifungal activity. Meanwhile, all isolated compounds, fractions, and the crude extract demonstrated extremely selective potent to moderate activity against Cryptococcus neoformans. The isolated five butyrolactone derivatives could develop potential mosquito larvicidal agents as a result of promising docking outcomes in the larval enzyme carboxylesterase.

Study on the solidification performance and mechanism of heavy metals by sludge/biomass ash ceramsites, biochar and biomass ash

Industrial by-products are stored in large quantities in the open, leading to wasted resources and environmental pollution, and the natural environment is similarly faced with phosphate depletion and serious water and soil pollution. This study uses these by-products to produce a new sludge/biomass ash ceramsite that will be used to adsorb nitrogen and phosphorus from wastewater, and solidify heavy metals in the soil while releasing Olsen P. The sludge/biomass ash ceramsites are made using sewage sludge and biomass ash in a certain ratio calcined at high temperatures and modified for the adsorption of nitrogen and phosphorus from wastewater. Sludge/biomass ash ceramsites before and after phosphorus adsorption, biochar and biomass ash were compared to analyze their heavy metal adsorption capacity and potential as phosphate fertilizer. After phosphorus adsorption, the sludge/biomass ash ceramsites released effective phosphorus steadily and rapidly in the soil, with a greater initial release than biochar and biomass ash, and the ceramsites were in a granular form that could be easily recycled. Biochar and biomass residue, due to their surface functional groups, are better at solidifying heavy metals than sludge/biomass ash ceramsites. Biochar, biomass ash and sludge/biomass ash ceramsites significantly reduced the concentrations of Cd, Cu, Pb and Zn in the soil. Correlation analysis demonstrated that there was a synergistic relationship between the increase in soil Olsen P content and the change in pH, with the increase in soil Olsen P content and the increase in pH contributing to heavy metal solidification.

Preparation of ceramsite using solid residue from anaerobic digestion of waste activated sludge and its enhancing effect on catalytic ozonation

Anaerobic digestion is an environmentally friendly method for reclaiming waste activated sludge. However, it cannot be overlooked that the solid residue generated from this process can still pose environmental risks and impose economic pressure on society. To mitigate and recycle the solid residue, this study utilized it as a primary raw material for manufacturing ceramsite with potential applications in wastewater treatment. The optimal ratio of solid residue to fly ash was demonstrated to be 6:4 with an additional 15% of clay supplementing the raw ceramsite materials. Furthermore, the optimal sintering process was established as preheating at 300 °C for 25 min followed by sintering at 1085 °C for 10 min, as determined through an L16 (44) Orthogonal test. The prepared ceramsite demonstrated advantageous performance parameters that exceeded the standards outlined in the Chinese industry standard CJ/T 299-2008 for water treatment artificial ceramsite. When utilized in an ozonation system, the ceramsite exhibited remarkable catalytic activity for phenol degradation by promoting the decomposition of molecular O3 into hydroxyl radicals. Additionally, it displayed minimal leaching of heavy metals and lower application costs. These findings emphasize its attractiveness in water and wastewater treatment processes and present a practical strategy for reclaiming this solid residue.

Chromatographic analysis and antioxidant potency of the crude extract of Xanthium spinosum in various fractions

Pharmacology experts place a high priority on therapeutic plants because the majority of pharmaceutical firms rely on medicinal plants as raw ingredients. Therefore, the potential bioactive components using gas chromatography-mass spectrometry analysis and antioxidant effects using DPPH free radical scavenging activity of various crude fractions of Xanthium spinosum were assessed. Gas chromatography-mass spectrometry analysis showed the presence of various bioactive compounds including benzenedicarboxylic acid (18.60%), 8-octadecenoic acid (4.86%), 11-octadecenoic acid and 10-octadecenoic acid in the crude methanolic extract, 1,2-benzenedicarboxylic acid, diisooctyl ester (14.42%), 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl) ester (14.42%), 6-octadecenoic acid, methyl ester (7.56%), 8-octadecenoic acid, methyl ester (7.56%), 10-octadecenoic acid, methyl ester (7.56%) and hexadecanoic acid, methyl ester (6.55%) in the n-hexane extract, ethanal, 2-methyl-2-[4-(1-methylethyl)phenyl]-(3.02%), (+)-3-carene, 4-isopropenyl-(3.02%), 7H-indeno[5,6-b] furan-7-one, 4,4a,5,6,7a,8-hexahydro- (3.02%) and 2-[5-(2,2-dimethyl-6-methylene-cyclohexyl)-3-methyl-pent-2-enyl]-[1,4] benzoquinone (2.79%) in the chloroform extract and 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl) ester (33.005%), 1,2-benzenedicarboxylic acid, diisooctyl ester (33.005%) and bis(2-ethylhexyl) phthalate (33.005%) in the ethyl acetate extract. Significant DPPH radical scavenging activity was exhibited by the chloroform fraction (43.37-88.65%) at all doses followed by the crude methanolic extract (36.02-83.75%) at all doses. In conclusion, different crude fractions of X. spinosum can be considered a rich source of pharmacologically active components that can be scoped for isolation and may be subjected to in-depth pharmacological study.

Enhanced biomethane production from waste activated sludge anaerobic digestion by ceramsite and amended Fe2O3 ceramsite

Wastes recycling and reutilization technique could simultaneously fulfill waste control and energy recovery sustainably, which has attracted increasing attention. This work proposed a novel waste reuse technology utilizing ceramsite and amended Fe2O3-ceramsite made from waste activated sludge (WAS) as additives to promote the yield of methane from WAS anaerobic digestion (AD). Experimental results demonstrated that compared to the control (85.05 ± 0.2 mL CH4/g-VS), the cumulative methane yield was effectively enhanced by 14% and 40% when ceramsite and Fe2O3-ceramsite were added. Further investigation revealed that ceramsite, especially the Fe2O3-ceramsite, enriched the populations of key anaerobes involved in hydrolysis, acidification, and methanogenesis. Meanwhile, potential syntrophic metabolisms between syntrophic bacteria and methanogens were confirmed in the Fe2O3-ceramsite AD system. Mechanisms studies exhibited that ceramsite and Fe2O3-ceramsite reinforced intermediate processes for methane production. The favorable pore structure, enhanced Fe (III) reduction capacity and conductivity also contributed a lot to the AD process.

Manufacturing non-sintered ceramsite from dredged sediment, steel slag, and fly ash for lightweight aggregate: production and characterization

Green and low-carbon materialization for dredged sediment (DS) is limited due to its low pozzolanic activity. In this study, a novel DS-based non-sintered lightweight aggregate (LWA) is developed by steel slag (SS) and fly ash (FA) activation. Process optimization is performed by the response surfaces, and the basic properties and characterization of the optimal product are investigated. Results indicated that the optimized design ceramic aggregate (ODCA) was prepared as follows: raw pellets comprising of 59.2% DS, 5% SS, 35.8% FA, 5% MK, 5% H2O2, and 2‰ foam stabilizer were activated by alkali activator (1.5 weight ratio of 14 M NaOH to water glass) and then cured at 80 °C and 95% humidity for 24 h. The basic and environmental performances of ODCA were in accordance with standards, whose bulk density was as low as 665.8 kg/m3, the high cylinder compressive strength was 6.143 MPa, and leaching concentrations of heavy metals were controllable. The regulation mechanism of LWA performances could be summarized as follows. SS and FA additives played the role for the mechanical strength enhancement and passivation of heavy metals, which promoted the formation of sillimanite, chabazite, and C-S-H / C-S-A-H gels in ODCA. The bulk density of ODCA was greatly reduced by H2O2 addition, where ODCA had an open-pore structure with a median pore size of 4969.75 nm. Note that C-S-H/C-S-A-H were the key hydration products to give ODCA light density and high mechanical strength, simultaneously.

Rapid screening and target-guided isolation of antioxidants from German chamomile by 2,2-diphenyl-1-picrylhydrazyl-ultra-high-performance liquid chromatography-mass spectrometry coupled with off-line two-dimensional high-speed countercurrent chromatography

German chamomile is one of the most effective herbal elements used in anti-allergic products and as an antioxidant. Herein, the antioxidant activity of different extract fractions of German chamomile was initially evaluated using an off-line 2,2-diphenyl-1-picrylhydrazyl spectrophotometric assay. The ethyl acetate extract demonstrated the highest efficacy in scavenging free radicals. Based on this, a rapid screening and separation method using ultra-high-performance liquid chromatography combined with the 2,2-diphenyl-1-picrylhydrazyl assay was implemented to identify antioxidants in the ethyl acetate fraction of German chamomile flowers. Ten potential radical scavengers were tentatively screened from German chamomile using a target-guided isolating approach with off-line two-dimensional high-speed countercurrent chromatography and the structures of the compounds were analyzed and identified. Ultimately, 10 radical scavengers were obtained from the ethyl acetate extract with a purity quotient exceeding 90%. The results demonstrated the effectiveness and reproducibility of this method for isolating potential antioxidants from complex mixtures in a targeted manner. This strategy can be applied to the target-guided isolation of complex mixtures of natural products with broad K-values and similar structures.

Surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes for the highly selective purification of resveratrol from crude extracts of Vitis vinifera, Arachis hypogaea, and Polygonum cuspidatum

In this work, surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes were prepared for the specific recognition and adsorption of resveratrol. The functionalization of magnetic multi-walled carbon nanotubes and the synthesis process of surface molecularly imprinted polymers were optimized. Characterizations were performed to demonstrate the successful synthesis of the imprinted materials. The imprinted materials showed satisfactory adsorption capacity of resveratrol (45.73 ± 1.72 mg/g) and excellent selectivity (imprinting factor 2.89 ± 0.15). In addition, the imprinted materials were used as adsorbents in molecularly imprinted solid-phase extraction for the purification of resveratrol from crude extracts of some food and medicinal resources, achieving recoveries of 93.69%-95.53% with high purities of 88.37%-92.33%. Moreover, the purified products exhibited extremely strong free radical scavenging activity compared with crude extracts. Overall, this work provided a promising approach for the highly selective purification of resveratrol from natural resources, which would contribute to the application of this valuable compound in the food/nutraceutical fields.

Nitro Indole Derivatives as Novel Dual-Polarity Matrices for MALDI Mass Spectrometry and Imaging with Broad Applications

A new matrix framework is presented in this study for the improved ionization efficiency of complex mixtures by matrix-assisted laser desorption ionization (MALDI) mass spectrometry/imaging. Five nitro indole (NI) derivatives [3-methyl-4-nitro-1H-indole (3,4-MNI), 3-methyl-6-nitro-1H-indole (3,6-MNI), 2,3-dimethyl-4-nitro-1H-indole (2,3,4-DMNI), 2,3-dimethyl-6-nitro-1H-indole (2,3,6-DMNI), and 4-nitro-1H-indole (4-NI)] were synthesized and shown to produce both positive and negative ions with a broad class of analytes as MALDI matrices. NI matrices were compared to several common matrices, such as 2,5-dihydroxybenzoic acid (DHB), alpha-cyano-4-hydroxylcinnamic acid (CHCA), sinapinic acid (SA), 1,5-diaminonaphthelene (1,5-DAN), and 9-aminoacridine (9-AA), for the analysis of lipid, peptide, protein, glycan, and perfluorooctanesulfonic acid (PFOS) compounds. 3,4-MNI demonstrated the best performance among the NI matrices. This matrix resulted in reduced ion suppression and better detection sensitivity for complex mixtures, for example, egg lipids/milk proteins/PFOS in tap water, while 2,3,6-DMNI was the best matrix for blueberry tissue imaging. Several important aspects of this work are reported: (1) dual-polarity ion production with NI matrices and complex mixtures; (2) quantitative analysis of PFOS with a LOQ of 0.5 ppb in tap water and 0.05 ppb in MQ water (without solid phase extraction enrichment), with accuracy and precision within 5%; (3) MALDI imaging with 2,3,6-DMNI as a matrix for plant metabolite/lipid identification with ionization enhancement in the negative ion mode m/z 600-900 region; and (4) development of a thin film deposition under/above tissue method for MALDI imaging with a vacuum sublimation matrix on a high-vacuum MALDI instrument.

Huaier Regulates Oxaliplatin Resistance in Colorectal Cancer by Regulating Autophagy and Inhibiting the Wnt/β-catenin Signalling Pathway

OBJECTIVE

The present study aims to investigate the effect of Huaier on oxaliplatin (OXA) resistance in HCT-8 colorectal cancer (CRC) cells.

METHODS

Oxaliplatin-resistant HCT-8/L CRC cells were used. The Cell Counting Kit-8, western blotting, quantitative real-time polymerase chain reaction, protein extraction kit, immunofluorescence and acridine orange staining assays were used in the study. The experiment results proved that Huaier has an influence on the Wnt/β-catenin signalling pathway, autophagy and drug resistance. The authors of the present study used chloroquine, an autophagy inhibitor and Wnt agonist 1 (a Wnt pathway agonist) to verify the present experiment.

RESULTS

The results showed that Huaier can regulate autophagy, inhibit the Wnt/β-catenin signalling pathway and reverse the drug resistance of OXA-resistant CRC cells.

CONCLUSIONS

This study proved that Huaier can regulate autophagy, inhibit the Wnt/β-catenin signalling pathway and reverse the drug resistance of OXA-resistant CRC cells.

Antitumoral photoinduced effects of crude extract, fractions, and naphthoquinones from Sinningia magnifica (Otto & A. Dietr.) Wiehler (Gesneriaceae) in a bioguided study

Photodynamic therapy (PDT) has been used for various purposes, including as an antitumor resource in a noninvasive therapy with minimal side effects. Sinningia magnifica (Otto & A. Dietr.) Wiehler is a rupicolous plant found in rock crevices in Brazilian tropical forests. Initial studies indicate the presence of phenolic glycosides and anthraquinones in species of the genus Sinningia (Generiaceae family). It is known that anthraquinones are natural photosensitizers with potential PDT applications. This led us to investigate the potential compounds of S. magnifica for use as a natural photosensitizer against the melanoma (SK-MEL-103) and the prostate cancer (PC-3) cell lines in a bioguided study. Our results showed that singlet oxygen production by the 1,3-DPBF photodegradation assay greatly increased in the presence of crude extract and fractions. The biological activity evaluation showed photodynamic action against melanoma cell line SK-MEL-103 and prostate cell line PC-3. These results suggest the presence of potential photosensitizing substances, as demonstrated in this in vitro antitumor PDT study by the naphthoquinones Dunniol and 7-hydroxy-6-methoxy-α-dunnione for the first time. Naphthoquinones, anthraquinones and phenolic compounds were identified in the crude extract by UHPLC-MS/MS analysis, motivating us to continue with the bioguided phytochemical study aiming to discover more photochemically bioactive substances in Gesneriaceae plants.

Huaier improves the efficacy of anti-PD-L1 Ab in the treatment of hepatocellular carcinoma by regulating tumor immune microenvironment

BACKGROUND

Combination therapy is an effective method for augmenting the efficacy of immune checkpoint inhibitors (ICIs). Huaier is a commonly used Chinese patent medicine with substantial antitumor effects. The combination of Huaier and ICIs may increase the efficacy of ICIs against hepatocellular carcinoma (HCC).

METHODS

The major components of Huaier were detected by high-performance liquid chromatography-mass spectrometry. The optimal antitumor dose of Huaier was investigated in H22-bearing mice. Next, Huaier was combined with anti-CD8α antibody (Ab) or anti-PD-L1 Ab to observe the antitumor effect. The safety of these combination drugs was evaluated through blood biochemical tests and hematoxylin and eosin staining of histological sections. RT-qPCR, immunohistochemistry, flow cytometry, and transcriptome sequencing were performed to investigate the potential action mechanism of anti-PD-L1 Ab combined with Huaier against HCC.

RESULTS

HPLC-MS/MS identified 333 components of Huaier, including carboxylic acids and derivatives, thienothiophenes, phenols, flavonoids and so on. Huaier exhibited significant antitumor effects, with the strongest effect noted at a dose of 4 g/kg. Huaier boosted CD8+ T cells infiltration into the tumor. Next, CD8+ T cells were depleted by with anti-CD8α Ab, and the antitumor effect of Huaier was suppressed. Flow cytometry results revealed that CD8+ T cells were reduced in the Huaier+anti-CD8α Ab group, with the antitumor effect of this group being inhibited. This indicated that CD8+ T cells were key players in the antitumor activity of Huaier. Meanwhile, Huaier inhibited microvessel density (MVD), downregulated vascular endothelial growth factor A (VEGFA), and upregulated PD-L1 in tumor tissues. Finally, Huaier combined with anti-PD-L1 Ab exhibited a greater antitumor effect in the H22-bearing mice. And the results of liver and kidney function tests and histological section analysis unveiled that the safety of these drugs was excellent. According to the transcriptome sequencing results, Huaier combined with anti-PD-L1 Ab possibly exerted anti-HCC effects through immunomodulation, immune response, and so on.

CONCLUSIONS

Huaier exhibited a significant antitumor effect. It promoted CD8+ T cells infiltration, upregulated PD-L1 expression, downregulated VEGFA expression, and inhibited MVD, thereby playing a significant antitumor immunoregulatory effect. The combination of Huaier and anti-PD-L1 Ab has significant antitumor effects, and this regimen has good safety. Therefore, Huaier combined with anti-PD-L1 Ab is a promising therapeutic approach against HCC.

Machine learning and traditional QSAR modeling methods: a case study of known PXR activators

Pregnane X receptor (PXR), extensively expressed in human tissues related to digestion and metabolism, is responsible for recognizing and detoxifying diverse xenobiotics encountered by humans. To comprehend the promiscuous nature of PXR and its ability to bind a variety of ligands, computational approaches, viz., quantitative structure-activity relationship (QSAR) models, aid in the rapid dereplication of potential toxicological agents and mitigate the number of animals used to establish a meaningful regulatory decision. Recent advancements in machine learning techniques accommodating larger datasets are expected to aid in developing effective predictive models for complex mixtures (viz., dietary supplements) before undertaking in-depth experiments. Five hundred structurally diverse PXR ligands were used to develop traditional two-dimensional (2D) QSAR, machine-learning-based 2D-QSAR, field-based three-dimensional (3D) QSAR, and machine-learning-based 3D-QSAR models to establish the utility of predictive machine learning methods. Additionally, the applicability domain of the agonists was established to ensure the generation of robust QSAR models. A prediction set of dietary PXR agonists was used to externally-validate generated QSAR models. QSAR data analysis revealed that machine-learning 3D-QSAR techniques were more accurate in predicting the activity of external terpenes with an external validation squared correlation coefficient (R2) of 0.70 versus an R2 of 0.52 in machine-learning 2D-QSAR. Additionally, a visual summary of the binding pocket of PXR was assembled from the field 3D-QSAR models. By developing multiple QSAR models in this study, a robust groundwork for assessing PXR agonism from various chemical backbones has been established in anticipation of the identification of potential causative agents in complex mixtures.

Cytotoxicity evaluation of phytochemicals from stingless bee (Tetragonula biroi) propolis

Three prenylated flavonoids (1-3) were isolated from Tetragonula biroi propolis. The structures of the isolated compounds were characterized by NMR, IR, and UV spectroscopic and mass spectrometric analyses. The cytotoxicity activity of the crude extracts, fractions and the isolated compounds were established against four cell lines such as Caco-2, HeLa, MCF-7, and OVK-18. Among the tested compounds, compound 1 showed cytotoxicity activity against MCF-7 cell lines, whereas compound 2 showed good activity against Caco-2 and OVK-18 cell lines with IC50 values of 14.73 and 14.44, respectively. Moreover, compound 3 exhibited strong activity against OVK-18 cell lines. These findings contribute to the phytochemical understanding of the T. biroi propolis, and their cytotoxicity effects for future pharmaceutical purposes.

The Apoptotic Property of Nymphaea Caerulea Flower Extract on Acute Myeloid Leukaemia Cell Line, THP-1

BACKGROUND

Acute Myeloid Leukaemia (AML) is considered to be an extremely heterogeneous malignancy of bone marrow and blood. The first line of therapy for AML is prolonged chemotherapy. Due to the presence of molecular heterogeneity in AML as confirmed by next-generation sequencing, researchers are planning to develop newer strategies of therapy.

OBJECTIVE

In the present study we have explored the anti-cancer potentiality of the hydro-ethanolic extract (50% and 70%) of the whole flower of Nymphaea caerulea against the Acute Myeloid Leukaemia cell line, THP-1 with control of normal human kidney epithelial cell line (HEK 293). The present study is a novel contribution to the existing scientific knowledge as at present no study as an anti-leukaemic agent is available on N. caerulea (blue lotus) extract and exploring its action mechanism on in-vitro cell line model.

METHODS

Some targeted cytokine and apoptotic genes genes to deduce the anti-cancer mechanism of action of the crude extract (hydro-ethanolic extract (50% and 70%) of the whole flower) were selected as Interferon (IFN) γ, Interleukins - IL-6, IL-8, IL- 10, IL-1β, Transforming Growth Factor (TGF β1), Tumor Necrosis Factor (TNF α), Caspase 3(CAS 3), Caspase 9 (CAS 9), CD95 (Fas), Tumor Necrosis Factor Receptor 1 (TNFRSF1A) to observe relative fold changes of the expression using Real-Time PCR with housekeeping gene β-actin. Cellular cytopathic effect (CPE), cell viability assay by methylene blue assay, and cell cytotoxicity of the crude extract against the THP-1 cell line were also studied along with it's bio-active compositional analysis of the extract was explored using ultra-performance liquid chromatography followed by mass spectra.

RESULTS

The N. caerulea flower extract is capable of inducing apoptosis in AML and it can balance cytokine alterations in such diseases.

CONCLUSIONS

Nymphaea caerulea flower extract appears to be a good anti-leukemia agent.

Endophytic fungi of Lycium barbarum: isolation, determination, bioactivity and separation of compounds

Lycium barbarum is widely distributed in China and used as a traditional Chinese medicine herb to treat dizziness, abdominal pain, dry cough, headache and fatigue. Several studies have examined the endophytes of L. barbarum from northwest China; however, few have focused on that from eastern China. The objective of this study was to isolate and determine the endophytic fungi of L. barbarum from Shandong province, as well as to obtain and identify active secondary metabolites from the endophytes. In this study, 17 endophytic fungi were isolated from L. barbarum and denoted as GQ-1 to GQ-17, respectively. These fungi were further classified into ten genera based on the morphological and ITS identification. The crude extracts of these fungi were obtained by using liquid fermentation and EtOAc extraction, and their antibacterial, cytotoxic, and antioxidant activities were evaluated. The results showed that GQ-6 and GQ-16 exhibited high inhibitory activity; GQ-6 and GQ-9 showed high cytotoxic activity and GQ-5 exhibited high scavenging capability for DPPH free radicals. Additionally, Cladosporium sp. GQ-6 was used to investigate the secondary metabolites. The crude extracts were purified by using column chromatography, reverse column, and liquid chromatography, and four monomeric compounds were identified, including two known compounds (α-acetylorcinol (1) and cladosporester B (2)) and two new compounds (cladosporacid F (3) and cladosporester D (4)). The anti-fungal and antibacterial activities of these compounds were confirmed, but no cytotoxic activity was observed. In conclusion, endophytic fungi of L. barbarum from eastern China can serve as a potential source of active natural products with antibacterial and antioxidant properties.

Detecting Submicromolar Analytes in Mixtures with a 5 min Acquisition on 600 MHz NMR Spectrometers

Amino compounds are widely present in complex mixtures in chemistry, biology, medicine, food, and environmental sciences involving drug impurities and metabolisms of proteins, biogenic amines, neurotransmitters, and pyrimidine in biological systems. Nuclear magnetic resonance (NMR) spectroscopy is an excellent tool for simultaneously identifying and quantifying these in-mixture compounds but has a limit-of-detection (LOD) over several micromolarities (>5 μM). To break such a sensitivity barrier, we developed a sensitive and rapid method by combining the probe-induced sensitivity enhancement and nonuniform-sampling-based 1H-13C HSQC 2D-NMR (PRISE-NUS-HSQC). We introduced two 13CH3 tags for each analyte to respectively increase the 1H and 13C abundances for up to 6 and 200 fold. This enabled high-resolution detection of 0.4-0.8 μM analytes in mixtures in 5 mm tubes with a 5 min acquisition on 600 MHz spectrometers. The method is much more sensitive and faster than traditional 1H-13C HSQC methods (∼50 μM, >10 h). Using sulfanilic acid as a single reference, furthermore, we established a database covering chemical shifts and relative-response factors for >100 compounds, enabling reliable identification and quantification. The method showed good quantitation linearity, accuracy, precision, and applicability in multiple biological matrices, offering a rapid and sensitive approach for quantitative analysis of large cohorts of chemical, medicinal, metabolomic, food, and other mixtures.

Novel Models for Accurate Estimation of Air-Blood Partitioning: Applications to Individual Compounds and Complex Mixtures of Neutral Organic Compounds

The air-blood partition coefficient (Kab) is extensively employed in human health risk assessment for chemical exposure. However, current Kab estimation approaches either require an extensive number of parameters or lack precision. In this study, we present two novel and parsimonious models to accurately estimate Kab values for individual neutral organic compounds, as well as their complex mixtures. The first model, termed the GC×GC model, was developed based on the retention times of nonpolar chemical analytes on comprehensive two-dimensional gas chromatography (GC×GC). This model is unique in its ability to estimate the Kab values for complex mixtures of nonpolar organic chemicals. The GC×GC model successfully accounted for the Kab variance (R2 = 0.97) and demonstrated strong prediction power (RMSE = 0.31 log unit) for an independent set of nonpolar chemical analytes. Overall, the GC×GC model can be used to estimate Kab values for complex mixtures of neutral organic compounds. The second model, termed the partition model (PM), is based on two types of partition coefficients: octanol to water (Kow) and air to water (Kaw). The PM was able to effectively account for the variability in Kab data (n = 344), yielding an R2 value of 0.93 and root-mean-square error (RMSE) of 0.34 log unit. The predictive power and explanatory performance of the PM were found to be comparable to those of the parameter-intensive Abraham solvation models (ASMs). Additionally, the PM can be integrated into the software EPI Suite, which is widely used in chemical risk assessment for initial screening. The PM provides quick and reliable estimation of Kab compared to ASMs, while the GC×GC model is uniquely suited for estimating Kab values for complex mixtures of neutral organic compounds. In summary, our study introduces two novel and parsimonious models for the accurate estimation of Kab values for both individual compounds and complex mixtures.

Introduction to the "Tracking complex mixtures of chemicals in human- and eco-exposome: the nexus of models, analytics, and toxicity" themed issue

Mingliang Fang, Beate Escher, Li Li and Zhenyu Tian introduce the Environmental Science: Processes and Impacts themed issue on “Tracking complex mixtures of chemicals in human- and eco-exposome: the nexus of models, analytics, and toxicity”.

Chemical, microbiological, textural, and sensory characteristics of pilot-scale Caciofiore cheese curdled with commercial Cynara cardunculus rennet and crude extracts from spontaneous and cultivated Onopordum tauricum

The aim of this study was the chemical, microbiological, textural, and sensory characterization of pilot-scale prototypes of an Italian ewe's raw milk cheese (Caciofiore) curdled with commercial Cynara cardunculus rennet, used as a control, and crude extracts obtained from flowers of either spontaneous or cultivated Onopordum tauricum. Hence, the control and experimental cheese prototypes produced in two rounds of cheesemaking trials were assayed, at the end of their 60-day maturation, for the following features: pH, titratable acidity, dry matter, fat, total and soluble nitrogen (TN and SN, respectively), ash, salt, protein, lactose, viable plate counts and composition of the bacterial and fungal populations, color, texture, volatile organic compounds (VOCs), and olfactory attributes by sensory analysis (the latter for the sole prototypes curdled with the commercial rennet and the extract obtained from cultivated O. tauricum). The data overall collected showed a very low impact of the type of thistle rennet on the analyzed cheese traits, with significant differences being exclusively found for SN/TN%, titratable acidity, color, and adhesiveness. By contrast, a higher impact of the cheesemaking round was seen, with significant differences being observed for salt content, load of presumptive lactobacilli, thermophilic cocci, and Escherichia coli, and levels of the following VOCs: 2,3-butanedione, 2-pentanone, 1-butanol, 2-heptanone, 3-methyl-1-butanol, 2-heptanol, 2-nonanone, dimethyl trisulfide, 2-methyl propanoic acid, butanoic acid, and 3-methyl butanoic acid. Sensory analysis revealed a strong ewe's cheese odor, accompanied by other olfactory notes, such as pungent, sour curd, sweet, and Parmesan cheese-like notes, in all the analysed cheese prototypes. Moreover, key odor active compounds, including butanoic acid, ethyl butanoate, 2,3-butanedione, 1-octen-3-one, and dimethyl trisulfide, were identified by GC-olfactometry analysis. Regarding the odor attributes as determined by sensory analysis, again the type of rennet had an almost negligible impact, with significant differences being only perceived for 1 or 2 out of 20 odor attributes, depending on the analytical conditions applied. Although some aspects deserve further investigation, the results herein collected confirm that O. tauricum can be regarded as an alternative source of thistle rennet for the manufacture of Caciofiore cheese, and more in general, Mediterranean ewe's milk cheeses.

A spectroscopic response factor-based toluidine blue assay towards a universal assay protocol for sulfated polysaccharides: Application to fucoidan content in crude extract

Sulfated polysaccharides (SPS) have attracted a lot of interest because of their diverse pharmacological functions. Numerous scientific studies have shown that SPS exhibit better biological activity than those that are not sulfated, such as immunomodulatory, anti-viral, and antioxidant activities. A crucial step to a better understanding of the mechanism of action and health effects is the production of high purity SPS. This calls for the development of selective assay techniques that can identify SPS preferentially without being influenced by other substances or the co-extracted polysaccharides. A universal modified toluidine blue (TB) assay was developed in this study to detect SPS. The assay procedures were conducted using different SPS standards including fucoidans from different biogenic sources, in addition to heparin and dextran sulfate. Spectroscopic response factor was calculated for each SPS which showed very good correlation (R2 = 0.998) with the corresponding sulfation degree. The proposed method was applied for determination of SPS content of crude fucoidan product using five different SPS standards. The method was cross validated by conducting ANOVA test to the obtained % recovery revealing that there is no significant difference between the results obtained by identical reference standard and four nonidentical natural SPS standards. This is the first report of a selective universal assay of SPS that enables the selective determination of SPS using a nonidentical reference standard.

Novel Biphasic In Vitro Dissolution Method Correctly Predicts the Oral Bioavailability of Curcumin in Humans

In vitro dissolution methods correctly predicting in vivo bioavailability of compounds from complex mixtures are lacking. We therefore used data on the in vivo performance of bioavailability-improved curcumin formulations to implement an in vivo predictive dissolution method (BiPHa+). BiPHa+ was applied for the characterization of eight curcumin formulations previously studied in a strictly controlled pharmacokinetic human trial. During dissolution, the dissolved proportion of curcumin in the aqueous medium underwent a formulation-dependent reduction, whereas the proportion remained stable in the organic layer. Compared with conventional dissolution systems, BiPHa+ was superior in terms of in vivo-relevant formulation characterization. All formulations could be precisely categorized according to their bioavailability in humans. In vitro-in vivo relationships for each dissolution method were established, with BiPHa+ providing the highest degree of linearity (r2 = 0.9975). The BiPHa+ assay correctly predicted the bioavailability of curcuminoids from complex mixtures and provided mechanistic information about formulation-dependent release characteristics.

Compatibility study of Duddingtonia flagrans conidia and its crude proteolytic extract

This study aimed to evaluate the concomitant use of the nematophagous fungus Duddingtonia flagrans (AC001) and its protease-rich crude extract for the in vitro control of Panagrellus sp., Haemonchus spp., and Trichostrongylus spp. The nematicidal tests were carried out on larvae of the free-living nematode Panagrellus sp. and infective larvae of the gastrointestinal parasitic nematodes of domestic ruminants (Haemonchus spp. and Trichostrongylus spp). Five experimental groups were set: (1) one control group (G1) and (4) four treated groups -G2 - active crude extract; G3 - denatured crude extract; G4 - fungus, and G5 - fungus + active extract. Plates were incubated at 28 ºC for 24 h followed by the recovery of the larvae using the Baermann technique. The results showed a lower recovery of Panagrellus sp. larvae in the experimental groups compared to the control group, as follows: 52 % (G2), 16 % (G3), 46 % (G4), and 77 % (G5). An even greater reduction (77 ± 5 %) occurred in the group (G5). In addition, the authors observed lower averages of L3 of Haemonchus spp. and Trichostrongylus spp. in the experimental groups compared to the control group, as follows: 59 % (G2), 0 % (G3), 86 % (G4), and 76 % (G5). In turn, there was a difference (p < 0.01) between (G5) and (G2). The results this study indicate a positive effect from the compatible use of the D. flagrans fungus and its enzymatic crude extract (protease), which has been demonstrated here for the first time and with potential field applications for further designs.

Cave Soil Streptomyces sp. strain YC69 Antagonistic to Chilli Fungal Pathogens Exhibits In Vitro Anticancer Activity Against Human Cervical Cancer Cells

Cancer is one of the fatal diseases and has high mortality worldwide, and the major drawback with the cure is the side effects from the chemotherapeutic agents. The increased multidrug resistance among microbial pathogens is a serious threat to plant and animal health. There is an urgent need for an alternative that can battle against pathogens and can be used for cancer treatment. Presently, actinomycetes were isolated from cave soil, and the crude extract obtained from the potent isolate was analyzed with gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC) to identify bioactive metabolites. The crude extract was examined for in vitro antimicrobial activity on human pathogens and antifungal activity on plant pathogens. The isolate Streptomyces sp. strain YC69 exhibited antagonistic activity and antimicrobial activity in a dose-dependent manner, with the highest inhibition in Staphylococcus aureus. GC-MS revealed many bioactive compounds, and HPTLC depicted metabolite fingerprints. The antifungal activity exhibited a delayed lag phase in growth curve assay and distorted and collapsed cells of Fusarium oxysporum in scanning electron microscopy (SEM) images. In the MTT assay, the IC50 of 41.98 µg/ml against HeLa cells was obtained with clear evidence for deformed cells and blebbing of the cell membrane. The results from the current study suggest that the crude extract from Streptomyces sp. strain YC69 contains antimicrobial metabolites that can inhibit pathogenic microbes in plants and humans. The MTT assay results conclude that further studies on purification may lead to the use of Streptomyces sp. strain YC69 as a source for anti-oncogenic compounds.

Facilitating structural elucidation of small environmental solutes in RPLC-HRMS by retention index prediction

Implementing effective environmental management strategies requires a comprehensive understanding of the chemical composition of environmental pollutants, particularly in complex mixtures. Utilizing innovative analytical techniques, such as high-resolution mass spectrometry and predictive retention index models, can provide valuable insights into the molecular structures of environmental contaminants. Liquid Chromatography-High-Resolution Mass Spectrometry is a powerful tool for the identification of isomeric structures in complex samples. However, there are some limitations that can prevent accurate isomeric structure identification, particularly in cases where the isomers have similar mass and fragmentation patterns. Liquid chromatographic retention, determined by the size, shape, and polarity of the analyte and its interactions with the stationary phase, contains valuable 3D structural information that is vastly underutilized. Therefore, a predictive retention index model is developed which is transferrable to LC-HRMS systems and can assist in the structural elucidation of unknowns. The approach is currently restricted to carbon, hydrogen, and oxygen-based molecules <500 g mol-1. The methodology facilitates the acceptance of accurate structural formulas and the exclusion of erroneous hypothetical structural representations by leveraging retention time estimations, thereby providing a permissible tolerance range for a given elemental composition and experimental retention time. This approach serves as a proof of concept for the development of a Quantitative Structure-Retention Relationship model using a generic gradient LC approach. The use of a widely used reversed-phase (U)HPLC column and a relatively large set of training (101) and test compounds (14) demonstrates the feasibility and potential applicability of this approach for predicting the retention behaviour of compounds in complex mixtures. By providing a standard operating procedure, this approach can be easily replicated and applied to various analytical challenges, further supporting its potential for broader implementation.

Characterization of the effect of pomegranate crude extract, and its post-harvesting preservation procedures, on redox tone, cellular growth and metabolic profile of MDA-MB-231 cell line

BACKGROUND

Pomegranate is known for its beneficial properties due to its high content in antioxidants and might constitute a natural option for preventing and treatment of different pathologies including cancer. Since mitochondria are involved in tumorigenesis through ROS production and modulation of oxidative metabolism, we investigated the biological effects of pomegranate on cellular redox state, proliferation and metabolism in the breast cancer cell line MDA-MB-231 (MDA).

METHODS

MDA were treated for 24 h with graded concentration of filtered Pomegranate juice (PJ) and tested for metabolic Flux Analysis with XFe96 Extracellular Flux Analyzer, for proliferation using the xCELLigence System Real-Time Cell Analyzer and for intracellular ROS content by Confocal Microscopy Imaging.

RESULTS

Cells-treatment with freshly prepared pomegranate juice (PJ) resulted in a significant reduction of the intracellular ROS content already at the lower concentration of PJ tested. Additionally, it enhanced mitochondria respiration, and decreased glycolysis at high concentrations, inhibiting at the same time cell proliferation. As pomegranate is a seasonal fruit, assessment of optimum storage conditions preserving its bio-active properties was investigated. Our results indicated that storage conditions under controlled atmosphere for 30 days was able to enhance mitochondrial respiration at the same extent than freshly extracted PJ. Conversely, freezing procedure, though retaining the antioxidant and cell-growth inhibitory property, elicited an opposite effect on the metabolic profile as compared with fresh extract.

CONCLUSION

Overall, the results of our study, on the one hand, confirms the preventive/therapeutic potential of PJ, as well as of its post-harvested processing, for cancer management. On the other hand, it highlights the intrinsic difficulties in attaining mechanistic insights when a multiplicity of effects is elicited by a crude mixture of bio-active compounds.

Global survey of dioxin- and thyroid hormone-like activities in consumer products and toys

BACKGROUND

Children and consumers are exposed to increasingly complex mixtures of known and as-yet-unknown toxic chemicals from toys and products. However traditional chemical analysis methods only evaluate a small number of chemicals at a time thereby restricting consumer awareness of the full range of potentially harmful chemicals in products.

METHODS

We used high-throughput effect-based non-animal methods to investigate exposures to complex chemical mixtures of several kinds of brominated flame retardants (BFRs) for their dioxin- and thyroid hormone-like activities in various kinds of consumer products and toys from 26 different countries, on four continents (Africa, America, Asia and Europe) in combination with chemical analysis of various polybrominated flame retardants (BFRs) and their impurities (such as polyhalogenated PCDD/Fs and PBDD/Fs).

RESULTS

We found high levels of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in toys and now, for the first time, also in consumer products that are manufactured from black plastics containing certain brominated flame retardants (BFRs). The presence of PBDD/PBDFs as well as other BFRs in various black plastic materials from additional countries as well as additional kinds of consumer products as confirmed by effect-based in vitro reporter gene DR CALUX and TTR-TRβ CALUX assays as well as congener-specific chemical analysis. We compared total Toxicity Equivalent (TEQ) levels of PBDD/F-TEQs analysed by chemical analysis to by CALUX bioassay measured Biological equivalence (BEQ) concentrations (for further info see at ISO 23196, ISO, 2022). In the case of TBBPA, both chemical and TTR-TRβ CALUX analysis measure direct the amount of TBBPA. Finally, the daily ingestion of 2,3,7,8-TCDD equivalents from PBDD/Fs-contaminated plastic toys by child mouthing habits have been related to our earlier study (Budin et al., 2020).

CONCLUSIONS

Interaction of children with such contaminated plastics may significantly contribute to the daily uptake of dioxin- and thyroid hormone transport disrupting-like compounds. Effect-based bioassays for dioxin- and thyroid hormone-like activities are relevant to pick-out such complex mixtures of known and yet unknown (and therefore not regulated) substances for safer and more sustainable plastics. Low POPs Content Levels and other mechanisms set under the Basel and Stockholm Conventions are set far too high to prevent a significant flow of BFRs and PBDD/Fs into consumer products.

Prospective In Vitro Comparison of Kerasave and Optisol-GS Corneal Storage Solutions

PURPOSE

The aim of this study was to compare the performance of Kerasave and Optisol-GS for hypothermic corneal storage for 14 days.

METHODS

This study was a prospective laboratory investigation. Mate corneas were recovered into Kerasave or Optisol-GS (27 pairs) and stored at 2°C to 8°C for 14 days. Corneas were evaluated by trained eye bank technicians, and study parameters were compared between the initial and final evaluations. Endothelial cell density (ECD), hexagonality (HEX), and coefficient of variation (CV) were evaluated by specular microscopy, and central corneal thickness (CCT) was examined by optical coherence tomography after 1, 3, 7, and 14 days of storage. Corneal transparency was scored using slit lamp examination at days 1 and 14.

RESULTS

Average ECD, HEX, and CV for the Kerasave (2653 ± 303 cells/mm 2 , 57 ± 4%, and 36 ± 3%) and Optisol-GS (2623 ± 306 cells/mm 2 , 57 ± 5%, and 36 ± 4%) groups were not significantly different at day 1. There was also no difference at any other study time points (all P > 0.05). ECD did not significantly change from day 1 to day 14 in either group ( P > 0.05), but a statistically significant change in HEX and CV was observed between day 1 and day 14 in both groups ( P < 0.01). Average CCT measured at day 1 for corneas stored in Kerasave was 622 ± 49 μm and those stored in Optisol-GS was 580 ± 35 μm ( P < 0.01). The difference in CCT measurements was not significantly different at day 14 (Kerasave: 674 ± 46 μm vs. Optisol-GS: 647 ± 58 μm, P > 0.05). Corneal transparency was not significantly different between the 2 groups at day 1 or day 14.

CONCLUSIONS

The corneal quality and clinically relevant parameters including ECD, endothelial morphometry, and corneal transparency were not different in corneas stored in Kerasave or Optisol-GS for 14 days. The initial difference in CCT between the 2 groups decreased at day 14. These results demonstrated that Kerasave corneal storage solution preserves the corneal endothelium similarly to Optisol-GS.

Complex mixtures of pesticides and metabolites modulate the malignant phenotype of murine melanoma B16-F1 cells

Pesticides use increased worldwide with a record in Brazil. Although several works addressed the effects of pesticides on living organisms, only a few considered their mixture, and even fewer tried to unravel their role in tumoral progression. Due to the relevance of cancer, in the present study, the effects of the mixture of pesticides widely used in Brazil (Glyphosate, 2,4-dichlorophenoxyacetic acid, Mancozeb, Atrazine, Acephate, and Paraquat) and their main metabolites (Aminomethylphosphonic Acid, 2,4-diclorophenol, Ethylenethiourea, Desethylatrazine, Methamidophos, and Paraquat) were investigated on the malignancy phenotype of murine melanoma B16-F1 cells after acute (24 h) and chronic (15 days) exposures. The tested concentrations were based on the Acceptable Daily Intake (ADI) value established by Brazilian legislation. The set of results showed that these chemicals modulate important parameters of tumor progression, affecting the expression of genes related to tumor aggressiveness (Mmp14 and Cd44) and multidrug resistance (Abcb1, Abcc1, and Abcc4), as well as tissue inhibitors of metalloproteinases (Timp1, Timp2, and Timp3). These findings revealed an absence of cytotoxicity but showed modulation of migration, invasion, and colonization capacity of B16-F1 cells. Together, the results point to some negative ways that exposure to pesticides can affect the progression of melanoma and raise a concern related to the increasing trend in pesticide use in Brazil, as the country is one of the major world food suppliers.

Exposure of zebrafish to an environmental mixture of persistent organic pollutants triggers an increase in anxiety-like syndrome but does not affect boldness in unexposed offspring

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants (POPs) that are present as complex mixtures in all environmental compartments, including aquatic ecosystems. However, little is known about the effects of such complex mixtures on teleost behaviour. In this study, zebrafish (Danio rerio) were chronically exposed to an environmentally relevant mixture (MIX) containing 22 PCB and 7 PBDE congeners through diet from 5 days post fertilization onwards. MIX-exposed F0 fish produced offspring (F1 and F2 generations) that were fed using plain food and grown until adulthood. In each generation, five behavioural traits (i.e. boldness, activity, sociality, exploration and anxiety) were evaluated by the mean of different experimental set-ups. Two distinct behavioural syndromes were identified: boldness, positively correlated to activity and exploration; and anxiety, associated with low sociality. F0 fish did not display any behavioural disruption resulting from POP exposure whereas F1 MIX fish were bolder than fish from other generations but did not differ significantly from F1 controls. F2 MIX fish displayed a higher anxiety syndrome than F2 controls. This is of particular importance since such behavioural changes in offspring generations may have persistent ecological consequences, may affect fitness and hence cause detrimental effects on wild fish populations exposed to POP mixtures.

Hormone receptor activities of complex mixtures of known and suspect chemicals in personal silicone wristband samplers worn in office buildings

Humans are exposed to increasingly complex mixtures of hormone-disrupting chemicals from a variety of sources, yet, traditional research methods only evaluate a small number of chemicals at a time. We aimed to advance novel methods to investigate exposures to complex chemical mixtures. Silicone wristbands were worn by 243 office workers in the USA, UK, China, and India during four work shifts. We analyzed extracts of the wristbands for: 1) 99 known (targeted) chemicals; 2) 1000+ unknown chemical features, tentatively identified through suspect screening; and 3) total hormonal activities towards estrogen (ER), androgen (AR), and thyroid hormone (TR) receptors in human cell assays. We evaluated associations of chemicals with hormonal activities using Bayesian kernel machine regression models, separately for targeted versus suspect chemicals (with detection ≥50%). Every wristband exhibited hormonal activity towards at least one receptor: 99% antagonized TR, 96% antagonized AR, and 58% agonized ER. Compared to men, women were exposed to mixtures that were more estrogenic (180% higher, adjusted for country, age, and skin oil abundance in wristband), anti-androgenic (110% higher), and complex (median 836 detected chemical features versus 780). Adjusted models showed strong associations of jointly increasing chemical concentrations with higher hormonal activities. Several targeted and suspect chemicals were important co-drivers of overall mixture effects, including chemicals used as plasticizers, fragrance, sunscreen, pesticides, and from other or unknown sources. This study highlights the role of personal care products and building microenvironments in hormone-disrupting exposures, and the substantial contribution of chemicals not often identifiable or well-understood to those exposures.

Risk from unintentional environmental mixtures in EU surface waters is dominated by a limited number of substances

Unintentional environmental mixtures happen when multiple chemicals co-occur in the environment. A generic mixture assessment factor (MAF), has been proposed to account for this. The MAF is a number by which safe exposure levels for single chemicals are divided to ensure protection against combined exposures to multiple chemicals. Two key elements to judge the appropriateness of a generic MAF are (1) defining the scope of mixtures that need to be addressed by a MAF (i.e.: simple mixtures vs complex mixtures), and (2) the existence of common risk drivers across large spatial scales. Simple mixtures with one to three risk drivers can easily be addressed by chemical-by-chemical regulatory action. Our work provides evidence on the prevalence and complexity of cumulative risk in EU freshwaters based on chemical monitoring data from one of the largest databases in the EU. With 334 chemicals being monitored, low complexity mixtures (one to 3 three risk drivers) dominated. After excluding metals, only 15 out of 307 chemicals (5 %) were most frequent chemical risk drivers. When these 15 chemicals were excluded from the analysis, 95 % of all monitoring site - year combinations did not pose a concern for cumulative risk. Most of these 15 chemicals are already banned or listed in various priority lists, showing that current regulatory frameworks were effective in identifying drivers of single chemical and cumulative risk. Although the monitoring data do not represent the entirety of environmental mixtures in the EU, the observed patterns of (1) limited prevalence of truly complex mixtures, and (2) limited number of overall risk drivers, argue against the need for implementing a generic MAF as a regulatory tool to address risk from unintentional mixtures in EU freshwaters.

Prioritization of mixtures of neurotoxic chemicals for biomonitoring using high-throughput toxicokinetics and mixture toxicity modeling

Modern society continues to pollute the environment with larger quantities of chemicals that have also become more structurally and functionally diverse. Risk assessment of chemicals can hardly keep up with the sheer numbers that lead to complex mixtures of increasing chemical diversity including new chemicals, substitution products on top of still abundant legacy compounds. Fortunately, over the last years computational tools have helped us to identify and prioritize chemicals of concern. These include toxicokinetic models to predict exposure to chemicals as well as new approach methodologies such as in-vitro bioassays to address toxicodynamic effects. Combined, they allow for a prediction of mixtures and their respective effects and help overcome the lack of data we face for many chemicals. In this study we propose a high-throughput approach using experimental and predicted exposure, toxicokinetic and toxicodynamic data to simulate mixtures, to which a virtual population is exposed to and predict their mixture effects. The general workflow is adaptable for any type of toxicity, but we demonstrated its applicability with a case study on neurotoxicity. If no experimental data for neurotoxicity were available, we used baseline toxicity predictions as a surrogate. Baseline toxicity is the minimal toxicity any chemical has and might underestimate the true contribution to the mixture effect but many neurotoxicants are not by orders of magnitude more potent than baseline toxicity. Therefore, including baseline-toxic effects in mixture simulations yields a more realistic picture than excluding them in mixture simulations. This workflow did not only correctly identify and prioritize known chemicals of concern like benzothiazoles, organochlorine pesticides and plasticizers but we were also able to identify new potential neurotoxicants that we recommend to include in future biomonitoring studies and if found in humans, to also include in neurotoxicity screening.

Detecting and Characterizing Interactions of Metabolites with Proteins by Saturation Transfer Difference Nuclear Magnetic Resonance (STD NMR) Spectroscopy

Saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy is an established technique for detecting and characterizing the binding of small molecules, such as metabolites, to biological macromolecules like proteins and nucleic acids. STD NMR allows detection of binding in complex mixtures of potential ligands, which is often used for library screening in the pharmaceutical industry but may also be beneficial for binding studies with metabolite mixtures. The nature of the ligand is normally restricted to small molecules in terms of NMR spectroscopy, and the size of the macromolecule on the other side should be larger than 10-15 kDa. This technique is especially applicable to detecting binders of intermediate to low affinity with the dissociation constant (K_D) above 1 μM. In this chapter, we focus on recent developments and the applications of STD NMR to studying interactions of natural products and metabolites, in particular. The reader is also referred to excellent reviews of the field and the literature cited therein. This chapter also provides a detailed experimental protocol for performing the STD NMR measurement based on the example of the subunit A of the Na⁺-transporting NADH/ubiquinone oxidoreductase (Na⁺-NQR) from V. cholerae interacting with its natural quinone substrate and inhibitors.

Fast and Sensitive Detection of Soil-Borne Cereal Mosaic Virus in Leaf Crude Extract of Durum Wheat

Soil-borne cereal mosaic virus (SBCMV) is a furovirus with rigid rod-shaped particles containing an ssRNA genome, transmitted by Polymyxa graminis Led., a plasmodiophorid that can persist in soil for up to 20 years. SBCMV was reported on common and durum wheat and it can cause yield losses of up to 70%. Detection protocols currently available are costly and time-consuming (real-time PCR) or have limited sensitivity (ELISA). To facilitate an efficient investigation of the real dispersal of SBCMV, it is necessary to develop a new detection tool with the following characteristics: no extraction steps, very fast results, and high sensitivity to allow pooling of a large number of samples. In the present work, we have developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) protocol with such characteristics, and we have compared it with real-time PCR. Our results show that the sensitivity of LAMP and real-time PCR on cDNA and RT-LAMP on crude extracts are comparable, with the obvious advantage that RT-LAMP produces results in minutes rather than hours. This paves the way for extensive field surveys, leading to a better knowledge of the impact of this virus on wheat health and yield.

Estrogenic and retinoid-like activity in stagnant waters with mass occurrence of water blooms

Stagnant freshwaters can be affected by anthropogenic pollution and eutrophication that leads to massive growth of cyanobacteria and microalgae forming complex water blooms. These can produce various types of bioactive compounds, some of which may cause embryotoxicity, teratogenicity, endocrine disruption and impair animal or human health. This study focused on potential co-occurrence of estrogenic and retinoid-like activities in diverse stagnant freshwaters affected by phytoplankton blooms with varying taxonomic composition. Samples of phytoplankton bloom biomass and its surrounding water were collected from 17 independent stagnant water bodies in the Czech Republic and Hungary. Total estrogenic equivalents (EEQ) of the most potent samples reached up to 4.9 ng·g^-1 dry mass (dm) of biomass extract and 2.99 ng·L^-1 in surrounding water. Retinoic acid equivalent (REQ) measured by in vitro assay reached up to 3043 ng·g^-1 dm in phytoplankton biomass and 1202 ng·L^-1in surrounding water. Retinoid-like and estrogenic activities at some sites exceeded their PNEC and effect-based trigger values, respectively. The observed effects were not associated with any particular species of cyanobacteria or algae dominating the water blooms nor related to phytoplankton density. We found that taxonomically diverse phytoplankton communities can produce and release retinoid-like compounds to surrounding water, while estrogenic potency is likely related to estrogens of anthropogenic origin adsorbed to phytoplankton biomass. Retinoids occurring in water blooms are ubiquitous signalling molecules, which can affect development and neurogenesis. Selected water bloom samples (both water and biomass extracts) with retinoid-like activity caused effects on neurodifferentiation in vitro corresponding to those of equivalent all-trans-retinoic acid concentrations. Co-occurrence of estrogenic and retinoid-like activities in stagnant water bodies as well as the potential of compounds produced by water blooms to interfere with neural differentiation should be considered in the assessment of risks associated with water blooms, which can comprise complex mixtures of natural and anthropogenic bioactive compounds.

Computational simulation of 1 H NMR profiles of complex biofluid analyte mixtures at differential operating frequencies: Applications to low-field benchtop spectra

Estimations of accurate and reliable NMR chemical shift values, coupling patterns and constants within a reasonable timeframe remain significantly challenging, and the unavailability of reliable software strategies for the prediction of low-field (e.g., 60 MHz) spectra from those acquired at higher operating frequencies hampers their direct comparison. Hence, this study explored the applications of accessible software options for predicting these parameters in the ¹ H NMR profiles of analytes as a function of magnetic field strength; this was performed for individual analytes and also for complex biofluid matrices featured in metabolomics investigations. For this purpose, results from the very first successful experimental acquisition and simulation of the ¹ H NMR profiles of intact human salivary supernatant samples on a 60 MHz benchtop spectrometer were evaluated. Using salivary metabolite concentrations determined at 400 MHz, it was demonstrated that simulation of the low-field spectra of five biomolecules with the most prominent ¹ H resonances detectable allowed multiple component fits to be applied to experimental spectra. Hence, these salivary ¹ H NMR profiles could be successfully predicted throughout the 45-600 MHz operating frequency range. With the exception of propionate resonance multiplets, which revealed more complex coupling patterns at low field and required more astute computational and fitting options, valuable quantitative metabolomics data on salivary acetate, formate, methanol and glycine could be attained from low-field spectrometres. These studies are both timely and pertinent in view of the recent advancement of low-field benchtop NMR facilities for diagnostically significant biomarker tracking in biofluids. Experiments performed with added ammonium chloride to facilitate the release of salivary metabolites from biopolymer binding sites provided evidence that a small but nevertheless significant proportion of propionate, but not lactate, was bound to such sites, an observation of much relevance to biomolecule quantification in salivary metabolomics investigations.

Polymer aging affects the bioavailability of microplastics-associated contaminants in sea urchin embryos

Microplastics (MPs) in the marine environment undergo complex weathering factors that can affect their ability to interact with different coexisting environmental contaminants (termed here co-contaminants). In this study, the influence of artificially aging using UV on the sorption of a complex mixture of co-contaminants onto MPs was investigated in order to provide meaningful hypotheses on their individual and combined toxicities on sea urchin embryos. A mixture of artificially aged MPs (PS particles and PA microfibers) combined with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), or Cd or Cu, both alone and in a mix, were used to expose embryos of Paracentrotus lividus. The effects of polymer aging on co-contaminants bioavailability were assessed by measuring changes in the transcriptional profile of genes involved in oxidative-stress response and skeletogenic and endo-mesodermal specification. Changes in the sorption ability of MPs to co-contaminants in the aqueous phase highlighted that aging did not affect the sorption of BDE-47 and Cd on MPs, although a certain influence on Cu sorption was found. Despite no morphological effects in embryos at the gastrula stage after MPs/contaminants combinatorial exposure emerged, the greatest influence of the aging process was mainly found for combined exposures which included BDE-47. Finally, the exposure to multiple contaminants generated transcriptional profiles poorly related to those activated by single contaminant, at times suggesting a mixture-dependent different aging influence. These results open new scenarios on the controversial role of vector of co-contaminants for MPs, especially when complex and different types of mixtures were considered.

Dietary exposure to environmentally relevant pesticide mixtures impairs swimming performance and lipid homeostatic gene expression in Juvenile Chinook salmon at elevated water temperatures

Aquatic organisms are exposed to complex mixtures of pesticides in the environment, but traditional risk assessment approaches typically only consider individual compounds. In conjunction with exposure to pesticide mixtures, global climate change is anticipated to alter thermal regimes of waterways, leading to potential co-exposure of biota to elevated temperatures and contaminants. Furthermore, most studies utilize aqueous exposures, whereas the dietary route of exposure may be more important for fish owing to the hydrophobicity of many pesticides. Consequently, the current study aimed to determine the effects of elevated temperatures and dietary pesticide mixtures on swimming performance and lipid metabolism of juvenile Chinook salmon, Oncorhynchus tshawytscha. Fish were fed pesticide-dosed pellets at three concentrations and three temperatures (11, 14 and 17 °C) for 14 days and swimming performance (U_max) and expression of genes involved in lipid metabolism and energetics were assessed (ATP citrate lyase, fatty acid synthase, farnesoid x receptor and liver x receptor). The low-pesticide pellet treatment contained five pesticides, p,p'-DDE, bifenthrin, esfenvalerate, chlorpyrifos and fipronil at concentrations based on prey items collected from the Sacramento River (CA, USA) watershed, with the high-pesticide pellet treatment containing a six times higher dose. Temperature exacerbated effects of pesticide exposure on swimming performance, with significant reductions in U_max of 31 and 23% in the low and high-pesticide pellet groups relative to controls at 17 °C, but no significant differences in U_max among pesticide concentrations at 11 or 14 °C. At 14 °C there was a significant positive relationship between juvenile Chinook salmon pesticide body residues and expression of ATP citrate lyase and fatty acid synthase, but an inverse relationship and significant downregulation at 17 °C. These findings suggest that temperature may modulate effects of environmentally relevant pesticide exposure on salmon, and that pesticide-induced impairment of swimming performance may be exacerbated under future climate scenarios.