Agricultural Herbicides Research Articles

Atrazine exposure in zebrafish induces aberrant genome-wide methylation

Atrazine (ATZ) is the second most common agricultural herbicide used in the United States and is an endocrine disrupting chemical (EDC). Developmental exposure to ATZ can lead to significant behavioral and morphological alterations in exposed animals and their progeny suggesting the involvement of an epigenetic mechanism. Specific epigenetic mechanisms responsible for these alterations, however, are yet to be elucidated. In this study, we exposed zebrafish embryos to 0, 0.3, 3, or 30 ppb (μg/L) of ATZ from 1 to 72 h post fertilization (hpf). Chemical exposure was ceased and zebrafish maintained until 9 months post fertilization (mpf), when whole-genome bisulfite sequencing (WGBS) was performed to assess the effects of embryonic ATZ exposure on DNA methylation in female fish brains. The number of differentially methylated genes (DMGs) increased with increasing treatment concentration. DMGs were enriched in neurological pathways with extensive methylation changes consistently observed in neuroendocrine pathways. Specifically, DMGs with methylation changes in promoter regions showed hypomethylation in estrogen receptor signaling and hypermethylation in androgen signaling. DMGs with methylation changes in genebody were primarily enriched for mitochondrion-related pathways associated with healthy aging. Integrated analysis with transcriptomic data at 9 mpf exhibited a similar trend identifying CABLES1 and NDUFA4 as shared targets at all concentrations. We then compared the predicted upstream regulators of transcriptomic changes with DMGs and identified CALML3 as a common upstream regulator at both 0.3 and 30 ppb that exhibit significant methylation changes. Collectively, our study identified long-lasting DNA methylation changes in genome after embryonic ATZ exposure and elucidated potential gene targets whose aberrant methylation features may drive alterations in gene transcription in long-term.

Impact of Soil Characteristics and Weed Management Practices on Glyphosate and AMPA Persistence in Field Crops Soils from the St. Lawrence Lowlands (Quebec, Canada)

The use of glyphosate-based herbicides (GBHs) in industrial agriculture has intensified in the past decades, causing a growing concern about the occurrence and spatial distribution of glyphosate and its principal metabolite, aminomethylphosphonic acid (AMPA), in the environment. In 2014, glyphosate and AMPA content was measured in 45 soils from the St. Lawrence Lowlands (Quebec, Canada) before seeding and at harvest in soybean field crops using various weed management practices with or without GBH applications. At the same time, a recent history of agricultural practices and soil conditions was compiled for the sampled sites. The results of the study show that 91% of the samples contained detectable amount of either glyphosate or AMPA, with maximum values of 0.47 mg·kg−1 and 1.16 mg·kg−1 for glyphosate and AMPA, respectively. Surprisingly, detectable amounts of AMPA were measured in fields not treated with GBHs in 2014, whereas traces of both glyphosate and AMPA were detected in organic field crops, highlighting the potential spreading and/or persistence of both compounds in the environment. Glyphosate content was significantly higher in clay soils rich in exchangeable cations, such as Mg2+, K+ and Ca2+, which can contribute to the retention of glyphosate in soil via complexation processes.

Preparation and characterization of chloridazon-loaded alginate/chitosan nanocapsules.

In addition to the detrimental environmental effects of herbicides, including the pollution of soil, atmosphere, groundwater aquifers and run-off water, the lack of caution and direct or indirect exposure to these products can cause short-term and long-term human health effects. However, nanotechnology, with its many applications, can be very helpful in improving agriculture and reducing the side effects of chemicals used in agriculture. Nano-encapsulation of chemicals used in agriculture is one of the strategies to improve precision agriculture. Nano-encapsulated herbicides are controlled membrane systems in which the active ingredient is coated with semi-permeable membranes, which may be organic or inorganic polymers. In our study, chloridazon herbicide was selected as the active ingredient for Nano-encapsulation. Like many other agricultural herbicides, the major problem with this herbicide is environmental pollution and its adverse health effects. The ionic gelation method was used to synthesize nanocapsules consisting of alginate and chitosan for chloridazon encapsulation. Alginate-chitosan nanoparticles were prepared in a two-step process involving the ionotropic pre-gelation of an alginate core and then the formation of a chitosan polyelectrolyte complex. The alginate-chitosan nanocapsules containing chloridazon were synthesized at a size of 253 nm with a polydispersity index (PDI) of 0.266 and a zeta potential of -1.43 mV. The loading capacity and entrapment efficiency of these nanocapsules were 14% and 57%, respectively. The study of chloridazon release from formulated alginate-chitosan nanocapsules was performed using dialysis tube testing and UV spectroscopy. The results of our study showed controlled release of chloridazon from loaded alginate-chitosan nanocapsules. In general, alginate-chitosan nanocapsules as a Nano-carrier, have the potential to become a commercial formulation for chloridazon encapsulation. On the other hand, controlled release and increasing the duration of action of chloridazon, along with reducing the required dose, is promising in reducing the adverse health and environmental effects caused by chloridazon and improving precision agriculture.

Do commonly used herbicides (atrazine and glyphosate) have the potential to impair the contractions, prostaglandin releasing and conducting of oxytocin signal at the bovine cervix in vitro?

Glyphosate (Gly) and atrazine (Atr) are among the most commonly used herbicides in global agriculture. It was previously shown that both Atr and Gly impair the ovarian and uterine secretion of regulators of myometrial motility (oxytocin (OT) or prostaglandins (PGs)) in cows, and Atr can also decrease the force of contractions in strips from the uterine horn. Hence, the aim of this study was to compare the effects of Atr and Gly on the motor and secretory function of the bovine cervix in vitro as well as receptivity and signal transduction in cervical cell cultures.Cervical strips or cells obtained from cows before ovulation were treated with environmental doses of Atr or Gly (0.1–10 ng/ml) since these herbicides exerted no cytotoxic effect at a dose of 100 ng/ml. Only Atr increased the force of cervical contractions, while both Atr and Gly decreased the secretion of prostaglandins (PGs) without disturbing their synthesis. Moreover, Atr decreased the mRNA expression and protein level of oxytocin receptor (OTR), while Gly increased OTR protein levels. Both Atr and Gly decreased the contents of gap junction proteins (GAPs), Atr decreased the contents of second messengers (diacylglycerol - DAG, inositol-tris-phosphate - IP3), and Gly decreased the level of myosin light chain kinase (MLCK) but increased DAG levels.Atr directly enhanced the cervical strips contractions. Both herbicides disturbed cellular signalling and inhibited PGs secretion. It suggest that Atr and Gly have the potential to impair the activity of cervical cells in vitro, which might be followed by failure of maintenance with gestation.

Deep Convolutional Neural Networks for Weeds and Crops Discrimination From UAS Imagery

Weeds are among the significant factors that could harm crop yield by invading crops and smother pastures, and significantly decrease the quality of the harvested crops. Herbicides are widely used in agriculture to control weeds; however, excessive use of herbicides in agriculture can lead to environmental pollution as well as yield reduction. Accurate mapping of crops/weeds is essential to determine weeds’ location and locally treat those areas. Increasing demand for flexible, accurate and lower cost precision agriculture technology has resulted in advancements in UAS-based remote sensing data collection and methods. Deep learning methods have been successfully employed for UAS data processing and mapping tasks in different domains. This research investigate, compares and evaluates the performance of deep learning methods for crop/weed discrimination on two open-source and published benchmark datasets captured by different UASs (field robot and UAV) and labeled by experts. We specifically investigate the following architectures: 1) U-Net Model 2) SegNet 3) FCN (FCN-32s, FCN-16s, FCN-8s) 4) DepLabV3+. The deep learning models were fine-tuned to classify the UAS datasets into three classes (background, crops, and weeds). The classification accuracy achieved by U-Net is 77.9% higher than 62.6% of SegNet, 68.4% of FCN-32s, 77.2% of FCN-16s, and slightly lower than 81.1% of FCN-8s, and 84.3% of DepLab v3+. Experimental results showed that the ResNet-18 based segmentation model such as DepLab v3+ could precisely extract weeds compared to other classifiers.

The association between urinary glyphosate and aminomethyl phosphonic acid with biomarkers of oxidative stress among pregnant women in the PROTECT birth cohort study

BackgroundGlyphosate is a widely used herbicide in global agriculture. Glyphosate and its primary environmental degradate, aminomethyl phosphonic acid (AMPA), have been shown to disrupt endocrine function and induce oxidative stress in in vitro and animal studies. To our knowledge, these relationships have not been previously characterized in epidemiological settings. Elevated urinary levels of glyphosate and AMPA may be indicative of health effects caused by previous exposure via multiple mechanisms including oxidative stress. MethodsGlyphosate and AMPA were measured in 347 urine samples collected between 16 and 20 weeks gestation and 24–28 weeks gestation from pregnant women in the PROTECT birth cohort. Urinary biomarkers of oxidative stress, comprising 8-isoprostane-prostaglandin-F2α (8-iso-PGF2α), its metabolite 2,3-dinor-5,6-dihydro-15-F2 t-isoprostane (8-isoprostane metabolite) and prostaglandin-F2α (PGF2α), were also measured. Linear mixed effect models assessed the association between exposures and oxidative stress adjusting for maternal age, smoking status, alcohol consumption, household income and specific gravity. Potential nonlinear trends were also assessed using tertiles of glyphosate and AMPA exposure levels. ResultsNo significant differences in exposure or oxidative stress biomarker concentrations were observed between study visits. An interquartile range (IQR) increase in AMPA was associated with 9.5% (95% CI: 0.5–19.3%) higher 8-iso-PGF2α metabolite concentrations. Significant linear trends were also identified when examining tertiles of exposure variables. Compared to the lowest exposure group, the second and third tertiles of AMPA were significantly associated with 12.8% (0.6–26.5%) and 15.2% (1.8–30.3%) higher 8-isoprostane metabolite, respectively. An IQR increase in glyphosate was suggestively associated with 4.7% (−0.9 to 10.7%) higher 8-iso-PGF2α. ConclusionsUrinary concentrations of the main environmental degradate of glyphosate, AMPA, were associated with higher levels of certain oxidative stress biomarkers. Associations with glyphosate reflected similar trends, although findings were not as strong. Additional research is required to better characterize the association between glyphosate exposure and biomarkers of oxidative stress, as well as potential downstream health consequences.

Chemometric evaluation of different parameters for removal of tembotrione (agricultural herbicide) from water by adsorption and photocatalytic degradation using sustainable nanotechnology

AbstractFractional multivariate design of experiments with seven factors was used to chemometrically evaluate adsorption of tembotrione on the surface of catalyst, efficiency of photocatalytic degradation of tembotrione, and removal efficiency. For adsorption, the experiments revealed two significant main effects (loading of TiO2 and concentration of KBrO3) and two interactions (loading of TiO2 × purging of O2 and loading of TiO2 × stirring during and 5 min before irradiation). Model for efficiency of photocatalytic degradation of tembotrione revealed three significant main effects (concentration of KBrO3, purging of O2, and stirring during and 5 min before irradiation), while overall removal efficiency had four significant main effects (concentration of KBrO3, purging of O2, loading of TiO2, and stirring during and 5 min before irradiation) and one two factor interaction (loading of TiO2 × concentration of KBrO3). The optimal removal yield of tembotrione was 99.5% with TiO2 loading of 1.25 mg/ml, KBrO3 concentration of 4.33 mM, β‐cyclodextrin with Au in the ratio 2:1, 3 ml/min O2 purging, and stirring before and during irradiation. The effect of tert‐butanol, NaF, EDTA × 2Na, and p‐benzoquinone on the tembotrione removal under optimal experimental conditions suggested that the relative contribution of various reactive species changed in following order: ˃ ●OHads ˃ h+ ˃ ●OHfree.

Assessing Occurrence and Biological Consequences of Contaminants of Emerging Concern on Oceanic Islands

Freshwater streams on oceanic islands serve critical ecological and economic functions. However, these are underrepresented in assessments of pollution from contaminants of emerging concern (CEC). Furthermore, freshwater streams and their endemic fauna often have characteristics that are distinct from those of continental streams and model species, calling extrapolations from studies of such systems into question for island streams. In the current study, we assessed the presence of CEC across three sampling events and five freshwater streams on the Island of Hawai’i. We also exposed juveniles of the native fish species Sicyopterus stimpsoni to a mixture of commonly co-occurring CEC for 96 h in static renewal experiments, testing for impacts of CEC in two ecologically relevant assays of functional performance. CEC from multiple sources were ubiquitous in Hawaiian streams, including human-use pharmaceuticals, agricultural herbicides, and industrial runoff. Concentrations of CEC were comparable to published studies from continental streams, exceeding total concentrations of 1000 ng/L for the eight quantified CEC in four samples, and approaching 2500 ng/L in one sample. Effects on exposed fish were subtle and limited to treatments with higher CEC concentrations but indicated potential impacts of CEC on locomotor performance. These results indicate that Hawaiian streams follow a global trend of widespread freshwater pollution by CEC that are accompanied by subtle effects on native fish species and highlight the need for the inclusion of endemic species and ecologically relevant assays when assessing the effects of contaminants in island habitats.

ДВУХКОМПОНЕНТНЫЙ ГЕРБИЦИД ХОРС Д, КС ДЛЯ ЗАЩИТЫ ПОСЕВОВ КУКУРУЗЫ

The research was carried out to assess the biological and economic effectiveness of the new two-component herbicide Hors D, KS (220 g/l dicamba (sodium salt) and 50 g/l nicosulfuron) of LLC “Agro Expert Group” on corn crops in Krasnodar Krai. The experiments were carried out in the field conditions of All-Russian Research Institute of Biological Plant Protection in 2018-2019 according to the methodological guidelines for registration tests of herbicides in agriculture. The soil is leached chernozem. The area of the plots is 25 m2, the repetition rate is 4 times, the flow rate of the working fluid is 200 l/ha. The experimental scheme included the use of the tested herbicide Hors D, KS in the application rates of 0.6; 0.8 and 1.2 l/ha. Carleone preparation was used as a standard, EC (0.3 and 0.6 l/ha) and control (without herbicides). The treatment was carried out in the phase of 3...5 leaves of the culture. The contamination of corn crops averaged 83 copies/m2. The herbicidal effect of the drugs was assessed by reducing the number and weight of weeds, as well as by the crop yield in comparison with the control. Weeds: common hedgehog, glaucous bristle, ragweed wormwood, tilted backward and Californian cocklebur showed a high sensitivity to drugs. The use of 0.6...1.2 l/ha of Hors D, KS led to an 80 ... 100% herbicidal effect. There was no negative effect of the drug for corn plants, crop yield increases were obtained, which amounted to 62.0...74.7% of the control. The obtained data for two years showed high biological and economic efficiency of the herbicide Hors D, KS against annual dicotyledonous and cereal weeds in corn crops

Agent Orange Chemical Plant Locations in the United States and Canada: Environmental and Human Health Impacts

During the Vietnam War, millions of liters of six tactical herbicides were sprayed on the southern Vietnam landscape to defoliate forests, to clear military perimeters and to destroy enemy food supplies. The environmental and human health impacts of spraying these herbicides, especially Agent Orange and those formulated with mixtures that included 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) which was contaminated with 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) have been documented over the last 60 years. The dioxin TCDD clean-up efforts at former military bases and other Vietnam hotspots are ongoing. However, the lesser-told story was the environmental and human health impacts on the communities and chemical plant workers who manufactured Agent Orange and other herbicides that became contaminated with dioxin TCDD in the manufacturing processes at seven locations in the United States and one site in Canada. The pollution at these chemical plant sites, adjacent rivers and groundwater is well known within each affected state or province but not widely recognized beyond their localities. In this paper we assess the national long-term effects on land, groundwater and river resources where Agent Orange and other agricultural herbicides containing 2,4,5-T with unknown amounts of dioxin TCDD were manufactured, transported, and temporarily stored. The sites where residual tactical herbicides with contaminated by-products were applied to public lands or disposed of by military and civilian workers within the United States and Canada are identified. After 60 years, these communities are still paying the price for the U.S. Government, DOD and USDA decisions to provide and use agricultural herbicides as tactical chemical weapons during the Vietnam War (1962-1971). There have been human health issues associated with the chemical manufacture, transport, storage and disposal of these herbicides related to workers who moved these chemical weapons from United States and Canada to SE Asia. Most of these dioxin contaminated tactical herbicides were transported via railroads to ports at Mobile, Alabama and Gulfport, Mississippi. They were then loaded on ocean-going ships and transported via the Panama Canal for use during the Vietnam War. The objective of this study is to document the environmental and human consequences of the manufacture of tactical herbicides with dioxin TCDD and arsenic on the chemical plant, transportation, application, storage and disposal workers. The costs of cleanup of these North America chemical plant sites, transportation corridors, temporary and long-term storage areas, supply chain storage facilities with residual tactical herbicide, application, and disposal sites to date, is in the billions of dollars. Billions have been spent on hazardous waste incineration to destroy the dioxin TCDD or bury it in certified landfills. Government mandated environmental covenants are on titles of properties still contaminated with high levels of dioxin TCDD. If landowners attempt to rescind land use restrictions, many more billions of dollars will be needed to finish the environmental cleanup and restore natural resources. These cost estimates do not include the billions of dollars needed to treat the effects of dioxin TCDD exposure of U.S. and Canadian civilian workers who manufactured and handled these contaminated herbicides during the Vietnam War as well as address human health issues of their offspring.

How United States Agricultural Herbicides Became Military and Environmental Chemical Weapons: Historical and Residual Effects

Discoveries in Charles Darwin’s laboratory led to modern herbicides. Darwin discovered the internal mechanism that directed plants to grow toward sunlight and sources of water. Scientists in Europe and America later called this mechanism a plant’s hormone response system. Administrators and scientists, including Dr. Ezra J. Kraus, the Head of the Botany Department at the University of Chicago and a plant physiologist, suggested on the eve of WWII that weed killers had significant military value as chemical weapons. Dr. Kraus obtained access to a synthetic chemical, 2,4-D, and found that when the chemical was absorbed through the leaves of plants, it destroyed a plant’s hormones. After exposure, the plant experienced rapid and uncontrolled growth, and then the leaves shriveled, died and fell off. Dr. Kraus obtained funding for his Department of Botany research program from Department of Defense (DOD) during World War II (WWII). Camp Detrick (Biological Weapons Laboratory) scientists later obtained samples of newly created 2,4,5-T which contained unknown amounts of the by-product dioxin TCDD. In the 1950s and 1960s, Fort Detrick military scientists formulated the herbicide Agent Orange, which was a 50 - 50 mixture of 2,4-D and 2,4,5-T. These dual purpose herbicides were used by DOD and USDA. American and European farmers in the 1940s used 2,4-D and 2,4,5-T to eliminate weeds from pastureland and cropland. After WWII, synthetic herbicides (and pesticides) development continued in tandem with production of synthetic fertilizers and breeding of high-yield plant varieties. These new agricultural products were then shipped worldwide to increase crop yields, as part of the Green Revolution. This new system of agricultural technologies was intended to eliminate global starvation and increase food security by increasing field and farm crop yields. In contrast, the goal of military use of herbicides, as chemical weapons, was to defoliate jungle forests and destroy food crops as a strategy to win battles and wars. The primary objective of this research study is to describe how agricultural herbicides became tactical chemical weapons. A current assessment will address the environmental impacts of military and environmental chemical weapons on the United States and Vietnam ecosystems and need for additional dioxin TCDD hotspot clean-up efforts.

Accumulation of commonly used agricultural herbicides in coral reef organisms from iSimangaliso Wetland Park, South Africa

Coral reefs are amongst the most biodiverse ecosystems on earth, but are significantly impacted by agricultural runoff. Despite herbicides being commonly detected in coastal waters, the possibility of herbicide accumulation in coral reef species has largely been overlooked. We investigate the accumulation of several herbicides in five species of coral reef invertebrates collected from ten sites along the Maputaland coast, South Africa. Multiple herbicide residues were detected in 95% of the samples, with total average concentrations across sites ranging between 25.2 ng g−1 to 51.3 ng g−1 dw. Acetochlor, alachlor and hexazinone were the predominant herbicides detected at all sites, with atrazine and simazine detected less frequently. Significant interactive effects were detected between sites nested in reef complex crossed with species, based on multiple and total herbicide concentrations. In general, multivariate herbicide concentrations varied significantly between species within and across most sites. Contrastingly, the concentrations of the different herbicides and that of total herbicide did not differ between conspecifics at most sites nested in their respective reef complexes. On average, highest total herbicide concentrations were measured in soft coral (Sarcophyton glaucum; 90.4 ± 60 ng g−1 and Sinularia gravis; 42.7 ± 25 ng g−1) and sponge (Theonela swinhoei; 39.0 ± 40 ng g−1) species, while significantly lower concentrations were detected in hard corals (Echinopora hirsutissima; 10.5 ± 5.9 ng g−1 and Acropora austera; 5.20 ± 4.5 ng g−1) at most sites. Agricultural runoff entering the ocean via the uMfolozi-St Lucia Estuary and Maputo Bay are likely sources of herbicide contamination to coral reefs in the region. There is an urgent need to assess the long-term effects of herbicide exposure on coral reef communities.

Evaluation of cameras and image distance for CNN-based weed detection in wild blueberry

Agricultural herbicide application efficiency can be improved using smart sprayers which provide site-specific, rather than broadcast, applications of agrochemicals. The YOLOv3-Tiny convolutional neural network (CNN) was trained to detect two weeds, hair fescue and sheep sorrel, in images captured from wild blueberry fields throughout Nova Scotia, Canada. An evaluation was performed in three commercial wild blueberry fields in Nova Scotia to examine the effects of camera selection and target distance on detection accuracy. A Canon T6 DSLR camera, an LG G6 smartphone, and a Logitech c920 webcam were used to capture RGB images at varying distances from target weeds. Mean F1-scores for each combination of camera and image height were analysed in a 3 × 3 factorial arrangement for hair fescue and a 3 × 2 factorial arrangement for sheep sorrel. Images captured from 0.98 m with the LG G6 and Canon T6 produced F1-scores of up to 0.97 for detection of at least one hair fescue tuft. Images captured with the LG G6 and Canon T6 DSLR from 0.57 m achieved F1-scores of 0.94 and 0.93, respectively, for detection of at least one sheep sorrel plant per image. Sheep sorrel was undetectable in images from the Logitech c920 under 19 of 27 parameter combinations. Future work will involve using the CNN to control herbicide applications with a real-time smart sprayer. Additionally, the CNN will be used in a web-based application to detect target weeds and provide site-specific information to aid management decisions. Using a CNN to detect weeds will create improvements in management techniques, resulting in cost-savings and greater sustainability for the wild blueberry industry.

A new method to co-design agricultural systems at the territorial scale - Application to reduce herbicide pollution in Martinique

CONTEXTChronic environmental pollutions are one of the most striking examples of negative externalities of intensive agriculture. To address this issue, an agroecological transition is necessary, requiring new design methods: While most design methods are suited to the field or farm scale, some innovations require an approach at the scale of the territory. OBJECTIVEIn this article, we propose a new method to design an agricultural territory aiming to overcome an environmental pollution issue, i.e. to identify one or more combinations of agricultural practices, implemented by the farmers of the territory that reduce water pollution. METHODSWe implemented the new method following three steps: first, we used a sociotechnical diagnosis to identify cognitive biases that prevent the actors from innovating in a disruptive way. Second, we used the KC method (based on CK theory) to allow actors to innovate in a disruptive way. Third, we used a serious game to continue the design of the innovations and to test and assess them in a safe place. We implemented this new method in the Galion River watershed in Martinique (French West Indies) whose river is polluted by herbicides. RESULTS AND CONCLUSIONUsing the method, actors have overcome existing path dependencies. Based on this, the method made it possible to design different innovations across scales in a participative way and with a systemic territorial point of view. Here, actors designed 15 innovations that enhance either the territory or the pooling of its resources. Among these, there was the sharing of the service of an itinerant breeder or the implementation of an ecotouristic circuit. Actors combined innovations across scales into three scenarios that created a new agricultural territory with fewer agricultural herbicides in the river. SIGNIFICANCEWe suggest adding two participatory steps to improve the level of genericity of the method: a first step to discuss the initial question and the general organisation of the participatory process, followed by a second step dealing with how to insert the designed innovations in the serious game. Finally, we recommend this method in other territories requiring collective practice changes.

Controllable Iterative β-Glucosylation from UDP-Glucose by Bacillus cereus Glycosyltransferase GT1: Application for the Synthesis of Disaccharide-Modified Xenobiotics.

Glycosylation in natural product metabolism and xenobiotic detoxification often leads to disaccharide-modified metabolites. The chemical synthesis of such glycosides typically separates the glycosylation steps in space and time. The option to perform the two-step glycosylation in one pot, and catalyzed by a single permissive enzyme, is interesting for a facile access to disaccharide-modified products. Here, we reveal the glycosyltransferase GT1 from Bacillus cereus (BcGT1; gene identifier: KT821092) for iterative O-β-glucosylation from uridine 5′-diphosphate (UDP)-glucose to form a β-linked disaccharide of different metabolites, including a C15 hydroxylated detoxification intermediate of the agricultural herbicide cinmethylin (15HCM). We identify thermodynamic and kinetic requirements for the selective formation of the disaccharide compared to the monosaccharide-modified 15HCM. As shown by NMR and high-resolution MS, β-cellobiosyl and β-gentiobiosyl groups are attached to the aglycone’s O15 in a 2:1 ratio. Glucosylation reactions on methylumbelliferone and 4-nitrophenol involve reversible glycosyl transfer from and to UDP as well as UDP-glucose hydrolysis, both catalyzed by BcGT1. Collectively, this study delineates the iterative β-d-glucosylation of aglycones by BcGT1 and demonstrates applicability for the programmable one-pot synthesis of disaccharide-modified 15HCM.

Current methods and technologies for degradation of atrazine in contaminated soil and water: A review

Atrazine is one of the most widely-used chlorine herbicides in agriculture. In recent years, studies have shown a potential hazard of atrazine use in environmental health and human health. Due to its toxicity, widespread use, relatively high stability in water and soil, determining safe and efficient methods of its removal is crucial. The main aim of this review was to showcase the recent progress of atrazine degradation methods, along with their main advantages, disadvantages, potential efficiency, and degradation pathways. The overall goal was to create an information gateway for researchers, and stakeholders interested in choosing the best method for atrazine degradation. Thus, the current technologies for atrazine degradation are systematically reviewed and can be used for future improvements or the selection of the most appropriate strategy for a specific place. • Atrazine is one of the most widely-used chlorine herbicides in agriculture. • A systematic review of novel methods of atrazine degradation. • Dealkylation and dechlorination are dominant pathways in atrazine degradation. • The physicochemical technologies are fast, efficient but invasive and expensive. • The biological methods are cheaper and environmentally safe but need improvement.

Synthesis, characterizations and kinetics of MOF‐5 as herbicide vehicle and its controlled release in PVA/ST biodegradable composite membranes

AbstractPolyvinyl alcohol/starch based composite membranes containing herbicide‐loaded metal‐organic‐framework (MOF‐5) was successfully synthesized by electrostatic spraying technique. Several main parameters affecting the adsorption of MOF‐5 were studied, including the initial concentration of the herbicide solution, adsorption time, and temperature. Under optimal conditions, herbicide‐loaded MOF‐5 was successfully synthesized and the main properties were characterized by Scanning Electron Microscopy (SEM), X‐Ray Diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetric Analysis (TG), and Brunauer‐Emmett‐Teller (BET), respectively. The results showed that the adsorption capacity of MOF‐5 at optimal conditions was 60.12wt%±0.61 % for atrazine. The sustained release effect of the AT@MOF‐5/PVA/ST composite membranes was reliable, and the cumulative release rate was about 50 % for 15 h. The release behaviour of AT from AT@MOF‐5/PVA/ST composite membranes was first dominated by the mechanism of Fickian diffusion and then by the mechanism of matrix erosion. The main advantages of agricultural herbicide film can be attributed to the eco‐friendly, biodegradable, and persistence of herbicide.

Paraquat-induced cholesterol biosynthesis proteins dysregulation in human brain microvascular endothelial cells

Despite Paraquat (PQ) being banned in several countries, it is still one of the most commonly used herbicides in agriculture. This compound is known to induce damaging effects on human and animal brain cells by generating Reactive Oxygen Species (ROS). However, there is few evidence of PQ effect on Human Brain Microvascular Endothelial Cells (HBMECs), one of the major component of the Blood–Brain Barrier (BBB). The present study aimed at unraveling biological mechanisms associated to the exposure of 1, 10 and 100 µM of PQ for 24 h on HBMECs. High-throughput mass spectrometry-based proteomics using data-independent acquisition (DIA) was applied. Biological pathway enrichment and cellular assays such as mitochondrial respiration and cholesterol level were performed to verify proteomics results. A total of 3753 proteins were quantified out of which 419 were significantly modulated by paraquat exposure. Biological pathway enrichment revealed the ubiquinone metabolism, a pathway directly linked to mitochondrial complex I proteins, confirming the well-known mechanism of PQ inducing oxidative stress. Additionally, this study also described the cholesterol biosynthesis modulation on HBMECs not yet described. In conclusion, our data indicate the toxic effect of PQ on HBMECs by downregulating proteins involved in mitochondrial complex I and cholesterol pathways.

Essential Oil-Based Bioherbicides: Human Health Risks Analysis.

In recent years, the development of new bio-based products for biocontrol has been gaining importance as it contributes to reducing the use of synthetic herbicides in agriculture. Conventional herbicides (i.e., the ones with synthetic molecules) can lead to adverse effects such as human diseases (cancers, neurodegenerative diseases, reproductive perturbations, etc.) but also to disturbing the environment because of their drift in the air, transport throughout aquatic systems and persistence across different environments. The use of natural molecules seems to be a very good alternative for maintaining productive agriculture but without the negative side effects of synthetic herbicides. In this context, essential oils and their components are increasingly studied in order to produce several categories of biopesticides thanks to their well-known biocidal activities. However, these molecules can also be potentially hazardous to humans and the environment. This article reviews the state of the literature and regulations with regard to the potential risks related to the use of essential oils as bioherbicides in agricultural and horticultural applications.

Design, synthesis, and herbicidal activity of novel phenoxypyridine derivatives containing natural product coumarin

In recent years, protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors have been widely studied as important agricultural herbicides. Our research focused on the design and synthesis of novel PPO inhibitor herbicides, through linking of a diphenylether pyridine bioisostere structure to substituted coumarins, which aims to enhance environmental and crop safety while retaining high efficacy. A total of 21 compounds were synthesized via acylation reactions and all compounds were characterized using infrared, 1 H NMR, 13 C NMR, and high-resolution mass spectra. The respective configurations of compounds IV-6 and IV-12 were also confirmed using single crystal X-ray diffraction. The bioassay results showed that the title compounds displayed notable herbicidal activity, particularly compound IV-6 which displayed better herbicidal activity in greenhouse and field experiments, crop selectivity and safety for cotton and soybean compared with the commercial herbicide oxyfluorfen. The work revealed that compound IV-6 deserves further attention as a candidate structure for a novel and safe herbicide. © 2021 Society of Chemical Industry.