The neonicotinoid insecticide imidacloprid has unexpected effects on the growth and development of soil amoebae

Effects of biochar and compost on microbial community assembly and metabolic processes in glyphosate, imidacloprid and pyraclostrobin polluted soil under freezethaw cycles

Biochar and organic compost are widely used in agricultural soil remediation as soil immobilization agents. However, the effects of biochar and compost on microbial community assembly processes in polluted soil under freezingthawing need to be further clarified. Therefore, a freezethaw cycle experiment was conducted with glyphosate (herbicide), imidacloprid (insecticide) and pyraclostrobin (fungicide) polluted to understand the effect of biochar and compost on microbial community assembly and metabolic behavior. We found that biochar and compost could significantly promote the degradation of glyphosate, imidacloprid and pyraclostrobin in freezethaw soil decrease the half-life of the three pesticides. The addition of immobilization agents improved soil bacterial and fungal communities and promoted the transformation from homogeneous dispersal to homogeneous selection. For soil metabolism, the combined addition of biochar and compost alleviated the pollution of glyphosate, imidacloprid and imidacloprid to soil through up-regulation of metabolites (DEMs) in amino acid metabolism pathway and down-regulation of DEMs in fatty acid metabolism pathway. The structural equation modeling (SEM) results showed that soil pH and DOC were the main driving factors affecting microbial community assembly and metabolites. In summary, the combined addition of biochar and compost reduced the adverse effects of pesticides residues.

Thymol's modulation of cellular macromolecules, oxidative stress, DNA damage, and NF-kB/caspase-3 signaling in the liver of imidacloprid-exposed rats

We evaluated whether thymol (THY) (30 mg/kg b.wt) could relieve the adverse effects of the neonicotinoid insecticide imidacloprid (IMD) (22.5 mg/kg b.wt) on the liver in a 56-day oral experiment and the probable underlying mechanisms. THY significantly suppressed the IMD-associated increase in hepatic enzyme leakage. Besides, the IMD-induced dyslipidemia was considerably corrected by THY. Moreover, THY significantly repressed the IMD-induced hepatic oxidative stress, lipid peroxidation, DNA damage, and inflammation. Of note, the Feulgen, mercuric bromophenol blue, and PAS-stained hepatic tissue sections analysis declared that treatment with THY largely rescued the IMD-induced depletion of the DNA, total proteins, and polysaccharides. Moreover, THY treatment did not affect the NF-kB p65 immunoexpression but markedly downregulated the Caspase-3 in the hepatocytes of the THY+IMD-treated group than the IMD-treated group. Conclusively, THY could efficiently protect against IMD-induced hepatotoxicity, probably through protecting cellular macromolecules and antioxidant, antiapoptotic, and anti-inflammatory activities.

A comprehensive evaluation of influencing factors of neonicotinoid insecticides (NEOs) in farmland soils across China: First focus on film mulching

Neonicotinoid insecticide (NEO) residues in agricultural soils have concerning and adverse effects on agroecosystems. Previous studies on the effects of farmland type on NEOs are limited to comparing greenhouses with open fields. On the other hand, both NEOs and microplastics (MPs) are commonly found in agricultural fields, but their co-occurrence characteristics under realistic fields have not been reported. This study grouped farmlands into three types according to the covering degree of the film, collected 391 soil samples in mainland China, and found significant differences in NEO residues in the soils of the three different farmlands, with greenhouse having the highest NEO residue, followed by farmland with film mulching and farmland without film mulching (both open fields). Furthermore, this study found that MPs were significantly and positively correlated with NEOs. As far as we know this is the first report to disclose the association of film mulching and MPs with NEOs under realistic fields. Moreover, multiple linear regression and random forest models were used to comprehensively evaluate the factors influencing NEOs (including climatic, soil, and agricultural indicators). The results indicated that the random forest model was more reliable, with MPs, farmland type, and total nitrogen having higher relative contributions.

Responses of Protozoan Communities to Multiple Environmental Stresses (Warming, Eutrophication, and Pesticide Pollution)

To explore the impacts of multiple environmental stressors on animal communities in aquatic ecosystems, we selected protozoa-a highly sensitive group of organisms-to assess the effect of environmental change. To conduct this simulation we conducted a three-factor, outdoor, mesocosm experiment from March to November 2021. Changes in the community structure and functional group composition of protozoan communities under the separate and combined effects of these three environmental stressors were investigated by warming and the addition of nitrogen, phosphorus, and pesticides. The results were as follows: (1) Both eutrophication and pesticides had a considerable promotional effect on the abundance and biomass of protozoa; the effect of warming was not considerable. When warming was combined with eutrophication and pesticides, there was a synergistic effect and antagonistic effect, respectively. (2) Eutrophication promoted α diversity of protozoa and affected their species richness and dominant species composition; the combination of warming and pesticides remarkably reduced the α diversity of protozoa. (3) Warming, eutrophication, and pesticides were important factors affecting the functional groups of protozoa. Interaction among different environmental factors could complicate changes in the aquatic ecological environment and its protozoan communities. Indeed, in the context of climate change, it might be more difficult to predict future trends in the protozoan community. Therefore, our results provide a scientific basis for the protection and restoration of shallow lake ecosystems; they also offer valuable insights in predicting changes in shallow lakes.

Soil physical structure drives N-glycan mediated trophic interactions in soil amoebae: Mechanisms and environmental implications

Soil protozoa are an essential part of the terrestrial ecosystem, playing a vital role in the global element cycling and energy flow. However, one research gap is what are the key factors driving their diversity and environmental fates. In this study, we hypothesized that soil texture could affect soil protozoa's predation and their interactions with environmental pollutants, and we tested it by using a soil amoeba Dictyostelium discoideum as a model system. We found that soil texture affected amoeba's growth and development. In addition, environmental factors cannot explain the variation of amoeba's fitness in different soil textures. Soil sandy particles and water content rather than particle size contribute to amoeba's fitness. Furthermore, different soil textures induced distinct transcriptional responses to amoebae, especially N-glycan-related and multiple signaling pathways and the expression of key genes (e.g., Ras superfamily, cxgE, trap1). The expression of N-glycan-related pathways, which is positively correlated with amoeba predation, was inhibited in sand soil, decreasing amoeba's fitness. Finally, the results showed that soil texture also affects amoeba's interaction with environmental pollutants. In conclusion, this study shows that soil physical structures affect amoeba's interactions with bacteria and environmental pollutants. SYNOPSIS: Soil texture affects soil protozoa's growth and development and their interactions with environmental pollutants.

Assessing the greenification potential of cyclodextrin-based molecularly imprinted polymers for pesticides detection

Cyclodextrins, with their unparalleled attributes of eco-friendliness, natural abundance, versatile utility, and facile functionalization, make a paramount contribution to the field of molecular imprinting. Leveraging the unique properties of cyclodextrins in molecularly imprinted polymers synthesis has revolutionized the performance of molecularly imprinted polymers, resulting in enhanced adsorption selectivity, capacity, and rapid extraction of pesticides, while also circumventing conventional limitations. As the concern for food quality and safety continues to grow, the need for standard analytical methods to detect pesticides in food and environmental samples has become paramount. Cyclodextrins, being non-toxic and biodegradable, present an attractive option for greener reagents in imprinting polymers that can also ensure environmental safety post-application. This review provides a comprehensive summary of the significance of cyclodextrins in molecular imprinting for pesticide detection in food and environmental samples. The recent advancements in the synthesis and application of molecularly imprinted polymers using cyclodextrins have been critically analyzed. Furthermore, the current limitations have been meticulously examined, and potential opportunities for greenification with cyclodextrin applications in this field have been discussed. By harnessing the advantages of cyclodextrins in molecular imprinting, it is possible to develop highly selective and efficient methods for detecting pesticides in food and environmental samples while also addressing the challenges of sustainability and environmental impact.

Changes in soil microbial communities after exposure to neonicotinoids: A systematic review

Neonicotinoids are a group of nicotine-related chemicals widely used as insecticides in agriculture. Several studies have shown measurable quantities of neonicotinoids in the environment but little is known regarding their impact on soil microbial populations. The purpose of this systematic review was to clarify the effects of neonicotinoids on soil microbiology and to highlight any knowledge gaps. A formal systematic review was performed following PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) guidelines using keywords in PubMed, SCOPUS and Web of Science. This resulted in 29 peer-reviewed articles, whose findings diverged widely because of variable methodologies. Field-based studies were few (28%). Imidacloprid was the most widely used (66%) and soil microbial communities were most sensitive to it. Spray formulations were used in 83% of the studies and seed treatments in the rest. Diversity indices were the most frequently reported soil microbial parameter (62%). About 45% of the studies found that neonicotinoids had adverse impacts on soil microbial community structure, composition, diversity, functioning, enzymatic activity and nitrogen transformation. Interactions with soil physicochemical properties were poorly addressed in all studies. The need for more research, particularly field-based research on the effects of neonicotinoids on soil microorganisms was highlighted by this review.

Co-exposure of dimethomorph and imidacloprid: effects on soil bacterial communities in vineyard soil

In Taiwan, the pesticides dimethomorph and imidacloprid are recommended for pest control in vineyards. Therefore, tank-mixing of these two pesticides is usually a routine practice before application. This study analyzed the influence of vineyard soil microbial flora under the recommended and high dosages (100 times the recommended dosage) of dimethomorph and imidacloprid. Individual and combined applications of pesticides were also tested through batches of soil incubation experiments. Four treatments-control (C), dimethomorph (DT), imidacloprid (IM), and mixed application of dimethomorph and imidacloprid (ID)-were used in the experimental design. From the soil metabolism, no significant reaction was observed after 2 months in the recommended dosage group, regardless of whether the pesticides were being applied individually or combined. For the high dosage, imidacloprid showed a higher effect than the co-exposure treatments, showing a possible prolonged effect after its repetitive application. From PCoA analysis, pesticide treatments altered the soil ecology after 2 months, and the effect of imidacloprid can be explicitly observed at high dosages. At the phylum level, Acidobacteria can indicate pesticide application around the recommended dosage. It was inhibited by ID on day 7 and was augmented by all pesticides on day 63. The effect of the recommended dosage of pesticide mixtures after 2 months of incubation was revealed in the minor families Gemmataceae and Pirellulaceae, while the high dosage treatments affected both the core and the minor families. Our findings verified the changes in the composition of microbial communities upon pesticide application, which would affect carbon, nitrogen, sulfur, phosphorous cycles, and contaminant removal ability within the vineyard.

Environmental stress promotes the persistence of facultative bacterial symbionts in amoebae

Amoebae are one major group of protists that are widely found in natural and engineered environments. They are a significant threat to human health not only because many of them are pathogenic but also due to their unique role as an environmental shelter for pathogens. However, one unsolved issue in the amoeba-bacteria relationship is why so many bacteria live within amoeba hosts while they can also live independently in the environments. By using a facultative amoeba- Paraburkholderia bacteria system, this study shows that facultative bacteria have higher survival rates within amoebae under various environmental stressors. In addition, bacteria survive longer within the amoeba spore than in free living. This study demonstrates that environmental stress can promote the persistence of facultative bacterial symbionts in amoebae. Furthermore, environmental stress may potentially select and produce more amoeba-resisting bacteria, which may increase the biosafety risk related to amoebae and their intracellular bacteria.