Synthesis of nano-Fe3O4/ZnO composites with enhanced antibacterial properties and plant growth promotion via one-pot reaction

Bordeaux mixture is commonly used in agricultural production due to its certain antibacterial activity. However, it has been observed to promote plant growth at a slow pace. Therefore, it is crucial to explore an effective antibacterial agent that can enhance the antibacterial activity and promote plant growth in commercially available Bordeaux mixture, which can significantly contribute to the development of the agricultural economy. The investigation into inorganic agents with both bacteriostatic and plant-promoting properties has a broad application potential in agriculture. Fe3O4/ZnO (FZ) composites were synthesized from FeCl3, ZnCl2, and NaAc in a "one-pot approach" and analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a vibrating sample magnetometer (VSM). To investigate the antibacterial activity and mechanism of FZ nanocomposites, Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were used as model bacteria, and human mammary epithelial cells and model plant mung bean were used as targets to study the effects of FZ on human and plant growth. The results revealed that at 300 µg/mL for 80 min, the antibacterial efficacy of FZ composites was 99.8% against E. coli, which was 20% greater than that of Bordeaux liquid (FC), and 99.9% against S. aureus, which was 28.6% higher than that of FC. The inhibitory mechanism demonstrated that the substance could efficiently damage the bacterial cell wall of a concentration of 300 µg/mL. The IC50 of the material to human mammary epithelial cells was 49.518 µg/mL, and it also increased mung bean germination, root growth, and chlorophyll content, indicating that the application performance was 1.5 times better than that of FC. Its exceptional performance can be used to treat agricultural diseases.

In silico prediction, characterization and molecular docking studies on Glutathione-S-transferase as a molecular sieve for toxic agrochemicals explored in survey of North Indian farmers

All across the globe, India is considered as an agricultural nation because its agro products drive the economy. An increase in population growth and a hike in food demands lead to the use of hazardous chemicals in farm fields. An in-depth field survey in Northern India was conducted to understand the types of agrochemicals that were used, farmers' knowledge about their safe handling, and their practices on its usage. Ninety-two responders (primarily farmers) from 37 districts of 12 states were interviewed to collect the information. The library containing 58 compounds as toxic spray constituents were developed and further screened in-silico for ADMET, drug-likeness, toxicity prediction, and molecular docking against their target actions in the human system. Glutathione S-transferases (GSTs) was selected as target protein showing the best-docked score with Bordeaux, Indoxacarb, Cyphenothrin, Deltamethrin, and Beta-cyfluthrin. The study revealed various adverse effects on human health and advocated provisions of alternative solutions such as using GST as a binding agents to hold the toxic chemicals out of living system and eventually saves valuable lives of the farmers.

Quantitative analysis of copper levels in areca nut plantation area - A role in increasing prevalence of oral submucous fibrosis: An in vitro study

Background

Oral submucous fibrosis (OSMF) commonly seen in the South Asian countries is mostly associated with the chewing of areca nut (AN). Copper content in the AN has been implicated to play a major role in the pathogenesis of OSMF. It was found that most of the AN plantations in South India commonly use a copper-based fungicide, Bordeaux mixture (BM).

Objective

To evaluate the level of copper in the AN, root, and soil of the AN plantation with and without the application of BM and to correlate the role of copper in the pathogenesis of OSMF.

Materials and Methods

ANs, roots, and soil were obtained from plantations located in Tanniadi, Kerala. Four areas were selected from the plantation with and without BM application. The samples were collected twice with the interval of 6 months during January 2015 and July 2015, respectively.

Statistical Analysis

Arithmetic mean and standard deviation were calculated. The differences between means were calculated by paired sample t-test.

Results

There was statistically significant difference in the copper content of ANs, soil, and roots from both groups (P < 0.05). Samples treated with BM showed significantly higher copper levels as compared to their counterparts in January and July 2015.

Conclusions

External copper from BM and increased processing for the commercial products could collectively increase the total copper content of the commercial AN products, and this high copper concentration may be implicated to the pathogenesis and the increasing prevalence of OSMF.

Effects of copper on the early development of Xenopus laevis: the case of CuSO4 and Bordeaux mixture solutions

Not available.

Adsorption behaviors of fungicide-derived copper onto various size fractions of aggregates from orchard soil

Although the gradual accumulations of Cu in orchard soils due to the application of Cu-based fungicides have been widely reported, limited information is available about the retention characteristics of fungicide-derived Cu in soil, especially in various size soil aggregates. This study described the adsorption characteristics of Cu from commonly used fungicide, Bordeaux mixture (CuSO₄ + Ca(OH)₂), onto various aggregate fractions (2000-1000, 1000-500, 500-250, 250-106, and <106 μm) of orchard soil. The Cu(NO₃)₂ was selected as a comparison. Two different types of adsorption experiments were conducted as follows: variable pH and variable Cu concentration experiments. The adsorption processes of Bordeaux mixture and Cu(NO₃)₂ onto the studied soil samples followed well with the Freundlich isotherm, and the adsorption isotherms were the S shaped. The adsorption amounts of Cu from different Cu compounds differed, and Bordeaux mixture can result in more Cu retention in soil than Cu(NO₃)₂. The adsorption ability of different size soil aggregates varied, and it was mainly governed by soil properties. The findings of this study suggested that both the chemical compositions of Cu compounds and the soil physical structure should be taken into account when performing soil Cu retention experiments with fungicide-derived Cu.

Metallothionein gene expression in embryos of the terrestrial snail (Cantareus aspersus) exposed to cadmium and copper in the Bordeaux mixture

The response specificity of three metallothionein (MT) genes (CdMT, CuMT and Cd/CuMT) was assessed after long-term exposure (20 days) of Cantareus aspersus eggs to cadmium (Cd) (2 to 6 mg/L) or to the fungicide Bordeaux mixture (BM) (2.5 and 7.5 g/L). MT gene expression measured by quantitative real-time PCR (qRT-PCR) revealed that in the unexposed embryos, the transcript levels of the three MT genes decreased significantly through embryonic development. However, the CdMT gene was strongly upregulated with increasing Cd exposure concentration, whereas the transcript levels of the other two genes increased less pronouncedly, but significantly above an exposure concentration of 4 mg Cd/L. Upon exposure to BM, all three MT genes were significantly upregulated above a BM concentration of 2.5 g/L. It is concluded that long-term Cd exposure in hatched snails induced patterns of MT gene expression that differed from those obtained after short-term exposure (24 h).

Metabolic changes of Vitis vinifera berries and leaves exposed to Bordeaux mixture

Since the development of Bordeaux mixture in the late 1800's, copper-based fungicides have been widely used against grapevine (Vitis vinifera L.) diseases, mainly in organic but also in conventional viticulture; however their intensive use has raised phytotoxicity concerns. In this study, the composition of grape berries and leaves upon Bordeaux mixture treatment was investigated during the fructification season by a metabolomic approach. Four applications of Bordeaux mixture till 3 weeks before harvest were performed following the regular management practices of organic viticulture. Results showed that the copper-based treatment affected the content in sugars, organic acids, lipids and flavan-3-ols of grapes and leaves at specific developmental stages. Nonetheless, the levels of sucrose, glucose and fructose, and of tartaric and malic acids were not significantly affected in mature grapes. In contrast, a sharp decrease in free natural amino acids was observed, together with a reduction in protein content and in mineral nitrogen forms. The treatment with Bordeaux mixture increased by 7-fold the copper levels in tissue extracts from surface-washed mature berries.

Evaluation of a Reduced Copper Spraying Program to Control Bacterial Blight of Walnut

Walnut blight, caused by Xanthomonas arboricola pv. juglandis, is currently controlled in western Europe through a standard schedule of seven applications of sprayed copper from bud break until harvest. A reduced spray schedule, with the last four applications omitted, was compared to the standard program in experimental plots for 3 years. Bacterial population levels in the spring were not significantly different between trees subjected to reduced sprays and those subjected to the standard schedule, but in summer they were higher in the trees that received fewer sprays compared with the standard program. However, disease control on nuts was similar or even better with the reduced spraying program than with the standard program, with the additional economic benefit of four fewer copper applications. After 3 years of using the reduced spray program, the amount of copper accumulated in the soil was significantly lower (about half) than that found in the soil where the standard spray program was implemented.