Characterization of the responses of soil micro-organisms to azoxystrobin and the residue dynamics of azoxystrobin in wheat-corn rotation fields over two years

Nontargeted screening of contaminants of emerging concern in the Nandu River Estuary

Contaminants of emerging concern (CECs) in estuaries have received increasing attention due to their potential environmental impacts. However, detailed analyses of the sources, transport mechanisms, and environmental consequences of these contaminants remain limited. This study applied non-target screening technology to comprehensively assess CECs in the Nandu River estuary. A total of 18,000 characteristic features were screened, revealing a greater number of hydrophobic features in seawater than in the estuary. Systematic classification identified 74, 195, and 48 compounds at Levels 1, 2, and 4 respectively, with primary classifications comprising pharmaceuticals (34 %), industrial materials (23 %), pesticides (18 %), and natural products (17 %). Semi-quantitative analysis employing external standards revealed elevated concentrations of 61 monitored contaminants in estuarine zones compared to offshore waters, with Climbazole exhibiting peak concentration levels. Ecological risk assessment identified 12 contaminants of emerging concern (CECs) requiring prioritized monitoring (with RQ > 1). A priority list was established based on the frequency of detection, bioaccumulation potential, persistence, toxicity and endocrine disruption potential of the compounds. 64 CECs were identified as high priority, consisting mainly of pesticides and pharmaceutical compounds. Pesticides originate primarily from upstream agricultural activities, decreasing in concentration downstream, whereas pharmaceuticals, industrial materials, and natural products are linked to domestic sewage. Tidal cycles play a crucial role in modulating the distribution and concentration of CECs within estuarine waters. This modulation is attributed to the dynamic interaction between terrestrial inputs and coastal influences, where high tides contribute significantly to the dilution of land-derived pollutants.

Bensulfuron methyl induced multiple stress responses in the field wheat plants: Microbial community and metabolic network disturbance

Sulfonylurea (SU) herbicides are widely used and often detected in environmental matrices and have toxic effects on ecosystems and plant development. However, the interaction between SU and soil-plant metabolism during the whole wheat growth cycle remains poorly investigated. Field trials demonstrated that bensulfuron methyl exposure reduced wheat height and a thousand grains' weight, disrupting the critical metabolic pathways, including linoleic acid and amino acid metabolism in the maturity stage. During different growth processes, bensulfuron methyl exposure decreases wheat soil and plants' defense-related indole alkaloid compounds, such as benzoxazinoids and melatonin. Microbial sequencing results showed that bensulfuron methyl treated decreased the abundance of beneficial microorganisms (Gammaproteobacteria, Bacteroidia, and Blastocatella) in the rhizosphere soil, which positively correlated with the inhibition of soil enzyme activity and the secretion of allelopathic substances (benzoxazinoids and melatonin). Molecular docking further confirmed that bensulfuron methyl affects protein molecular structure by establishing hydrogen bonds, which disequilibrate wheat benzoxazinoids and melatonin metabolism. Therefore, bensulfuron methyl exposure disrupted the interaction between soil microorganisms and indole alkaloid metabolism, hindering plant development. This study provides constructive insights into the environmental risks of herbicides and agricultural product safety throughout wheat development.

Response of Soil Microbiota, Enzymes, and Plants to the Fungicide Azoxystrobin

The present study was aimed at assessing the impact of azoxystrobin-a fungicide commonly used in plant protection against pathogens (Amistar 250 SC)-on the soil microbiota and enzymes, as well as plant growth and development. The laboratory experiment was conducted in three analytical terms (30, 60, and 90 days) on sandy clay (pH-7.0). Azoxystrobin was applied to soil in doses of 0.00 (C), 0.110 (F) and 32.92 (P) mg kg-1 d.m. of soil. Its 0.110 mg kg-1 dose stimulated the proliferation of organotrophic bacteria and actinobacteria but inhibited that of fungi. It also contributed to an increase in the colony development index (CD) and a decrease in the ecophysiological diversity index (EP) of all analyzed groups of microorganisms. Azoxystrobin applied at 32.92 mg kg-1 reduced the number and EP of microorganisms and increased their CD. PP952051.1 Bacillus mycoides strain (P), PP952052.1 Prestia megaterium strain (P) bacteria, as well as PP952052.1 Kreatinophyton terreum isolate (P) fungi were identified in the soil contaminated with azoxystrobin, all of which may exhibit resistance to its effects. The azoxystrobin dose of 0.110 mg kg-1 stimulated the activity of all enzymes, whereas its 32.92 mg kg-1 dose inhibited activities of dehydrogenases, alkaline phosphatase, acid phosphatase, and urease and stimulated the activity of catalase. The analyzed fungicide added to the soil at both 0.110 and 32.92 mg kg-1 doses inhibited seed germination and elongation of shoots of Lepidium sativum L., Sinapsis alba L., and Sorgum saccharatum L.

Carvacrol Encapsulation in Chitosan-Carboxymethylcellulose-Alginate Nanocarriers for Postharvest Tomato Protection

Advancements in polymer science and nanotechnology hold significant potential for addressing the increasing demands of food security, by enhancing the shelf life, barrier properties, and nutritional quality of harvested fruits and vegetables. In this context, biopolymer-based delivery systems present themselves as a promising strategy for encapsulating bioactive compounds, improving their absorption, stability, and functionality. This study provides an exploration of the synthesis, characterization, and postharvest protection applications of nanocarriers formed through the complexation of chitosan oligomers, carboxymethylcellulose, and alginate in a 2:2:1 molar ratio. This complexation process was facilitated by methacrylic anhydride and sodium tripolyphosphate as cross-linking agents. Characterization techniques employed include transmission electron microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, thermal analysis, and X-ray powder diffraction. The resulting hollow nanospheres, characterized by a monodisperse distribution and a mean diameter of 114 nm, exhibited efficient encapsulation of carvacrol, with a loading capacity of approximately 20%. Their suitability for phytopathogen control was assessed in vitro against three phytopathogens-Botrytis cinerea, Penicillium expansum, and Colletotrichum coccodes-revealing minimum inhibitory concentrations ranging from 23.3 to 31.3 μg·mL-1. This indicates a higher activity compared to non-encapsulated conventional fungicides. In ex situ tests for tomato (cv. 'Daniela') protection, higher doses (50-100 μg·mL-1, depending on the pathogen) were necessary to achieve high protection. Nevertheless, these doses remained practical for real-world applicability. The advantages of safety, coupled with the potential for a multi-target mode of action, further enhance the appeal of these nanocarriers.