Commercial beekeepers in many locations are experiencing increased annual colony losses of honey bees (Apis mellifera), but the causes, including the role of agrochemicals in colony losses, remain unclear. In this study, we investigated the effects of chronic consumption of pollen containing a widely-used fungicide (Pristine®), known to inhibit bee mitochondria in vitro, which has recently been shown to reduce honey bee worker lifespan when field-colonies are provided with pollen containing field-realistic levels of Pristine®. We fed field colonies pollen with a field-realistic concentration of Pristine® (2.3 ppm) and a concentration two orders of magnitude higher (230 ppm). To challenge flight behavior and elicit near-maximal metabolic rate, we measured flight quality and metabolic rates of bees in two lower-than-normal air densities. Chronic consumption of 230 but not 2.3 ppm Pristine® reduced maximal flight performance and metabolic rates, suggesting that the observed decrease in lifespans of workers reared on field-realistic doses of Pristine®-laced pollen is not due to inhibition of flight muscle mitochondria. However, consumption of either the 230 or 2.3 ppm dose reduced thorax mass (but not body mass), providing the first evidence of morphological effects of Pristine®, and supporting the hypothesis that Pristine® reduces forager longevity by negatively impacting digestive or nutritional processes.

Antibiotic resistance genes (ARGs) are emerging contaminants that pose a potential risk to human health worldwide. In this study, a metagenomic analysis was performed to investigate the distribution of ARGs in paddy field ecosystems, crayfish monoculture pond ecosystems, and rice-crayfish cultivation field ecosystems. The results showed that MacB and BcrA are two dominant ARGs, and macrolide is the dominant antibiotic not only in the water, but also in the sediment and gut of crayfish, in both the crayfish monoculture and the rice-crayfish cultivation ecosystems. Meanwhile, some lower-abundance ARGs in the water and sediment of crayfish cultivation ecosystems were significantly different in their abundance than those in rice paddy fields, and the ARGs in crayfish culture system and rice paddy fields showed even higher dissimilarities of diversity. Comprehensive analysis with redundancy analysis（RDA）and the distribution of dominant ARGs showed that the dissimilarity was related to the higher concentrations of total nitrogen (TN), total phosphorus (TP), chlorophyll a (Chla), permanganate index (CODMₙ₎, and nitrate in the water of rice paddy fields, and was related to the higher contents of N, P, K, and organic matter (OM) in the sediment of rice paddy fields. The source trackers of ARGs within the crayfish cultivation ponds and the rice-crayfish cultivation fields showed that the sediment in crayfish cultivation ponds mainly played the role of the ‘sink’ for ARGs, and the water and gut of crayfish mutually contributed to the high rates of ARGs. The ARG contribution rates of crayfish gut and sediment decreased and increased, respectively, in rice-crayfish cultivation fields and in crayfish monoculture ponds, which might be related to the lower crayfish biomass and the lower water depth in rice-crayfish cultivation fields.

Horse mackerel is a semi-pelagic species found in abundance in the Moroccan coasts and occupies the first ranks in the catches landed by the coastal fleet. In this study, we investigated the ingestion of Polyamide, Acrylic and Polystyrene by Atlantic horse mackerel, in the Moroccan Atlantic coastal area located between Larache (35°30′N) and Boujdour (26°30′N). The objective is to map the spatial distribution of horse Mackerel containing microplastics (MPs) in their stomachs and identify hot spot areas. We also aim to verify the most ingested polymer by this fish characterized by significant daily vertical migrations. The results show that the three studied polymers were detected in the stomach contents of more than 73% of studied fishes. The hot spot areas are located more in the northern part where urbanization and fishing activity are important. Polyamide, the densest polymer, is the most abundant (86% of cases), followed by acrylic. These two polymers were found in association in 47% of cases. No correlation between the presence of MPs in the stomach contents and the size of the individual fishes was noted. Interestingly, the group of mature specimens ingested more MPs than the immature group.

Polyaromatic phenanthrene (Phe) and benzo[a]pyrene (BaP) are highly toxic, mutagenic, and carcinogenic contaminants widely dispersed in nature, including saline environments. Polyextremotolerant Rhodotorula mucilaginosa EXF-1630, isolated from Arctic sea ice, was grown on a huge concentration range -10 to 500 ppm- of Phe and BaP as sole carbon sources at hypersaline conditions (1 M NaCl). Selected polycyclic aromatic hydrocarbons (PAHs) supported growth as well as glucose, even at high PAH concentrations. Initially, up to 40% of Phe and BaP were adsorbed, followed by biodegradation, resulting in 80% removal in 10 days. While extracellular laccase, peroxidase, and un-specific peroxygenase activities were not detected, NADPH-cytochrome c reductase activity peaked at 4 days. The successful removal of PAHs and the absence of toxic metabolites were confirmed by toxicological tests on moss Physcomitrium patens, bacterium Aliivibrio fischeri, human erythrocytes, and pulmonary epithelial cells (A549). Metabolic profiles were determined at the midpoint of the biodegradation exponential phase, with added Phe and BaP (100 ppm) and 1 M NaCl. Different hydroxylated products were found in the culture medium, while the conjugative metabolite 1-phenanthryl-β-D-glucopyranose was detected in the medium and in the cells. Transcriptome analysis resulted in 870 upregulated and 2,288 downregulated transcripts on PAHs, in comparison to glucose. Genomic mining of 61 available yeast genomes showed a widespread distribution of 31 xenobiotic degradation pathways in different yeast lineages. Two distributions with similar metabolic capacities included black yeasts and mainly members of the Sporidiobolaceae family (including EXF-1630), respectively. This is the first work describing a metabolic profile and transcriptomic analysis of PAH degradation by yeast.

This manuscript describes the reuse of biowaste for the biosynthesis of silver nanoparticles (AgNPs) and their applications. In particular, we hypothesized that the phytochemicals in the onion peels could act as reductant for silver nanoparticles syntheses. AgNO₃ solution (1 mmol) was added dropwise to an aqueous solution of onion peel extract in 3:7 ratio. The reaction mixture was subjected to heating at 90 °C for about 30 min. During the synthesis of the AgNPs, the change of the colour of solution was observed. The AgNPs solution was centrifuged to obtain the two layers, which consists of clear solution and solid layers at 12000 rpm for 30 min. The precipitate was filtered and was re-dispersed in deionised water (25 mL). The solution was centrifuged again to obtain the purified AgNPs. Subsequently, this solution was freeze dried for 48 h to afford the powdered AgNPs. In this work, the structure of the AgNPs were synthesized in spherical shape, with an average size of 12.5 nm observed in the Transmission electron microscopy (TEM) analysis. For catalytic application, the synthesized AgNPs could be applied as green catalyst to promote Knoevenagel and Hantzsch reactions. In most cases, the desired products were obtained in satisfactory yields. In addition, the AgNPs were found to be recyclable for the subsequent reactions. After five successive runs, the average isolated yields for both transformations were recorded to be 91% (Knoevenagel condensation) and 94% (Hantzsch reaction), which indicated that the existing AgNPs could apply as green catalyst in the field of organic synthesis. Furthermore, the AgNPs also showed satisfactory result in antioxidant activity. The current results indicate that the AgNPs can act as alternative antioxidant agent and green catalyst in mediating organic transformations.

The co-contamination by perfluoroalkyl acids (PFAAs) and heavy metals (HMs) is ubiquitous in the surface environment subjected to sewage irrigation and land application of sludge. However, the joint effects of HMs and PFAAs on plant roots are not well clarified. This study explored the root uptake and acropetal translocation behaviors of C2–C8 PFAAs by wheat (Triticum acstivnm L.) under the co-exposure of copper (Cu). The underlying uptake mechanisms of PFAAs were verified in a defective root system. The results showed that excessive Cu (100–400 μmol/L) damaged the cell membrane of wheat root to increase electrolytic leakage. In the defective root system, the root concentrations of PFAAs decreased by 6%–73% and the decrease rates were negatively associated with the carbon chain length of PFAAs. Along with the decrease in root concentrations of PFAAs, the amount of ultrashort-chain (C2–C3) and short-chain (C4–C6) PFAAs translocated to the shoot also decreased by 45%–84%. In contrast, the acropetal translocation of long-chain (C8) PFAAs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), was enhanced under Cu exposure due to the increase in root permeability as observed by increased electrolytic leakage. The shoot concentrations of PFOA and PFOS under Cu exposure were up to 5.5 and 11 times higher than those in the control, respectively. These results suggested that PFOA and PFOS could enter wheat root more easily through the breaks caused by Cu exposure and thereby their acropetal transportation to shoot was enhanced. Therefore, the risk of plant accumulation of long-chain PFAAs can be potentially underestimated if without considering the co-contamination with HMs in the environment.

Ammonia is essential for the generation of secondary inorganic aerosols (SIA) in particulate matter, which affects severely the air quality in north China. In this study, PM₂.₅ sampling was conducted as well as gaseous pollutant concentration and meteorological parameters were measured from November 2017 to January 2018. PM₂.₅ concentration was highest in the industrial site (94.8 ± 41.7 μg m⁻³), followed by urban (40.9 ± 24.1 μg m⁻³) and rural (35.6 ± 20.3 μg m⁻³) sites. The mass ratio of NO₃⁻/SO₄²⁻ exhibited clear site variations, with the highest average value of 1.2 was found at the urban site, likely due to the dense traffic volume resulting in higher emissions of NO₂, and the lowest value of 0.9 at the industry site. The presence of Excess-NHx (E-NHx), raising the pH 24 by 1.4, 1.3, and 1.4 units in industry, urban, and rural sites, respectively, might be vital for raising the aerosol pH. Correlation coefficients of Nitrogen oxidation rate (NOR, NOR = [NO₃⁻]/[NO₃⁻] + [NO₂]) vs. Photochemical oxidants (Oₓ, NO₂ +O₃ in our study) and NOR vs. aerosol water content (AWC) at three sites were implied that both homogeneous and heterogeneous reactions occurred for nitrate formation in industry site, while heterogeneous reactions were dominant in urban and rural sites. Oxidation rates were most sensitive to the variation of E-NHx concentration at rural site, followed by the urban and industry sites, which was shown by the fact that the increase in E-NHx concentration by 1.0 μg m⁻³ increased the SIA concentration by 1.21, 1.02, and 0.37 μg m⁻³ at rural, urban, and industry sites, respectively. With the increase in NHₓ emissions at present, the role of NHₓ in SIA formation at ammonia-rich atmosphere requires more attention, especially in the less-noticed rural areas.

Studies on the effects of trace elements (TEs) (e.g. Cu, Cd, Zn) on soil microbial communities have provided useful information on the toxicity of TEs to microbes. However, previous studies mainly focused on the effects of TEs on microbial community structure in intact soil, while there are few studies on the impact of TEs on microbial community structure in soil aggregates. In this study, soils previously polluted for 20 years, and now containing low and high TE concentrations derived from, now abandoned, metal smelters were sampled from the surface layer (0–15 cm) of two adjacent Chinese paddy fields. The aim was to determine the effects of TEs on the soil microbial biomass and community structure in different sized soil aggregates. Long-term high TE pollution decreased microbial biomass concentration and species, changed the proportion of bacteria and fungi and decreased the diversity of bacteria in the different sized aggregates. The microbial communities in soil aggregates became clustered with increasing TE concentrations.

With numerous new chemicals introduced into the environment everyday, identification of their potential hazards to the environment and human health is a considerable challenge. Developing adverse outcome pathway (AOP) framework is promising in helping to achieve this goal as it can bring In Vitro testing into toxicity measurement and understanding. To explore the toxic mechanism underlying environmental chemicals via the AOP approach, an integration of adequate experimental data with systems biology understanding is preferred. Here, we describe a novel method to develop reliable and sensible AOPs that relies on chemical-gene interactions, toxicity pathways, molecular regulations, phenotypes, and outcomes information obtained from comparative toxicogenomics database (CTD) and Ingenuity Pathway Analysis (IPA). Using Benzo(a)pyrene (BaP), a highly studied chemical as a stressor, we identified the pivotal IPA toxicity pathways, the molecular initiating event (MIE), and candidate key events (KEs) to structure AOPs in the liver and lung, respectively. Further, we used the corresponding CTD information of multiple typical AHR-ligands, including 2,3,7,8-tetrachlorodibenzoparadioxin (TCDD), valproic acid, quercetin, and particulate matter, to validate our AOP networks. Our approach is likely to speed up AOP development as providing a time- and cost-efficient way to collect all fragmented bioinformation in published studies. It also facilitates a better understanding of the toxic mechanism of environmental chemicals, and potentially brings new insights into the screening of critical paths in the AOP network.