Bioefficacy, environmental safety and synergistic impacts of biorational formulations against whitefly, leafhopper and blister beetle in organic okra ecosystem

Whitefly (Bemisia tabaci Gennadius), leafhopper (Amrasca biguttula biguttula Ishida) and large yellow-banded blister beetle (Mylabris phalerata) cause considerable damage to okra, especially under organic farming. Thus, the present study was carried out to test the bioefficacy and environmental safety of six naturally derived components [indigenous water plant extracts, i.e. chilli (Capsicum annum), garlic (Allium sativum L.) and neem (Azadirachta indica A. Juss.) along with cow urine in three different combinations, one commercial botanical (azadirachtin 0.15%), and two formulated entomopathogenic fungi (Verticillium lecanii and Beauveria bassiana)] on aforesaid pests for two consecutive years at field scale. In addition to this, the eco-toxicological effect of naturally derived components was also studied on natural enemies’ populations, viz. spiders and coccinellids. Quaternary mixture application of chilli, garlic, neem leaf and cow urine (CGNC) at 10% w/v was found effective in reducing leafhoppers (94.6%), whiteflies (95.2%) and blister beetle (94.6%) over control. Okra treated with CGNC produced a higher marketable fruit yield (18.44 mg/ha) than those of other treatments. It was also observed that the application of CGNC had no phytotoxic symptoms on okra plants. Application of CGNC was found safer to the natural enemy's population (spiders and coccinellids). Thus, the study suggests that CGNC can be considered as a potential source for managing the population of whitefly, leafhopper and blister beetle without affecting the ecology of natural enemies and it could be a viable eco-friendly option in organic okra production for ensuring food safety and healthy environment.

Toxicity of Quaternary Mixture of Formulated Glyphosate and Phenols on Providencia vermicola Dehydrogenase Activity

Aims: To assess the toxicity of glyphosate (as an active ingredient in drysate), three phenols (2,4-dichlorophenol, 4-chlorophenols and phenol) and quaternary mixtures of glyphosate, 2,4-dichlorophenol, 4-chlorophenol and phenol on the dehydrogenase activity (DHA) of P. vermicola. Study Design: The glyphosate, 2,4-dichlorophenol, 4-chlorophenol and phenol mixture ratios (%) were designed as: 25%:25%:25%:25%; 30%:20%:20%:30%, 40%:10%:10%: 40%; 50%:5%:30%:15% and 20%:20%:10%:50% for the respective mixtures in the concentration range of 0-1000 mg/L. Place and Duration of Study: Silver Press Laboratory, Owerri Nigeria between July, 2016 and August, 2019. Methodology:A laboratory scale study was carried on four toxicants using dehydrogenase inhibition test. The inhibition of dehydrogenase activity of the isolate by toxicant was calculated relative to the control. The percentage inhibition data generated was fitted into a logistic dose response model and Weibulleum to obtain their respective IC50. Results:The results revealed that the median inhibitory concentrations (IC50) of the mixtures on the Providencia vermicola were 247.17 ±10.20, 163.44 ± 8.18, 251.33 ± 45.25, 267.30 ± 8.76 and 178.93 ± 45.53 mg/L, respectively. Toxicity index (TI) model was used to evaluate the joint action toxicity of the mixtures on the test organism and was 60 % antagonistic. Conclusion: Thus, these synergistic and additive interactions of formulated glyphosate with the intermediates of 2,4-D was possible against the dehydrogenase activity of Providenciavermicola an important plant growth promoting bacterium. The dynamics of the toxic effects thus would depend on the concentration of the compounds.

Diffusion in multicomponent aqueous alcoholic mixtures

The Fick diffusion coefficient matrix of the highly associating quaternary mixture water + methanol + ethanol + 2-propanol as well as its ternary and binary subsystems is analyzed with molecular dynamics simulation techniques. Three of the ternary subsystems are studied in this sense for the first time. The predictive capability of the employed force fields, which were sampled with the Green–Kubo formalism and Kirkwood–Buff integration, is confirmed by comparison with experimental literature data on vapor-liquid equilibrium, shear viscosity and Fick diffusion coefficient, wherever possible. A thorough analysis of the finite size effects on the simulative calculation of diffusion coefficients of multicomponent systems is carried out. Moreover, the dependence of the Fick diffusion coefficient matrix on the velocity reference frame and component order is analyzed. Their influence is found to be less significant for the main matrix elements, reaching a maximum variation of 19%. The large differences found for the cross elements upon variation of the reference frame hinder a straightforward interpretation of the Fick diffusion coefficient matrix with respect to the presence of diffusive coupling effects.

Multivariate optimization and evaluation of quaternary mixture in bulk and co-formulated dosage forms by central composite design

Background The current study describes the use of central composite design for multivariate optimization of resolution and retention time, taking into account different critical method parameters like organic phase, pH, flow rate, and wavelength for risk assessment. The chromatographic method for the assay of the most effective anti-viral regimen (EPCLUSA, DARVONI, and HARVONI) was developed. An experimental design was presented by sequential investigation of four independent parameters. The method was developed using XTERRA C18 (250 mm × 4.6 mm, 5 μm particle size) column in isocratic mode using potassium dihydrogen phosphate buffer (pH adjusted to 5) and acetonitrile (50:50 % v/v) as mobile phase at a flow rate of 1.0 ml/min and UV detection wavelength of 260 nm. Results The separation of four drugs with fine resolution and preferable retention times was achieved. Retention times of four drugs were found to be 2.96, 3.91, 7.15, and 11.94 min for daclatasvir, sofosbuvir, velpatasvir, and ledipasvir, respectively. The percentage accuracy of labelled claim was in the range of 99–102%, and the pooled %RSD for repeatability, precision, and accuracy was less than 2%. Conclusion The suggested method was applied for quantification and identification of studied drugs in tablets; the results agreed with the label claim and were validated according to the ICH guidelines. The optimized method can be used for pharmacokinetic and quality control studies.

Mixing crop residues induces a synergistic effect on microbial biomass and an additive effect on soil organic matter priming

Applying crop residues is a widely used strategy to increase soil organic matter (SOM) in arable soils because of its recorded effects on increasing microbial biomass and consequently necromass. However, fresh residue inputs could also prime the decomposition of native SOM, resulting in accelerated SOM depletion and greenhouse gas (GHG) emission. Increasing the botanical diversity of the crops grown in arable systems has been promoted to increase the delivery of multiple ecological functions, including increasing soil microbial biomass and SOM. Whether mixtures of fresh residues from different crops grown in polyculture contribute to soil carbon (C) pools to a greater extent than would be expected from applying individual residues (i.e., the mixture produces a non-additive synergistic effect) has not been systematically tested and is currently unknown. In this study, we used 13C isotope labelled cover crop residues (i.e., buckwheat, clover, radish, and sunflower) to track the fate of plant residue-derived C and C derived from the priming of SOM in treatments comprising a quaternary mixture of the residues and the average effect of the four individual residues one day after residue incorporation in a laboratory microcosm experiment. Our results indicate that, despite all treatments receiving the same amount of plant residue-derived C (1 mg C g-1 soil), the total microbial biomass in the treatment receiving the residue mixture was significantly greater, by 26% (3.69 μg C g-1), than the average microbial biomass observed in treatments receiving the four individual components of the mixture one day after applying crop residues. The greater microbial biomass C in the quaternary mixture, compared to average of the individual residue treatments, that can be attributed directly to the plant residue applied was also significantly greater, by 132% (3.61 μg C g-1). However, there was no evidence that the mixture resulted in any more priming of native SOM than average priming observed in the individual residue treatments. The soil microbial community structure, assessed using phospholipid fatty acid (PLFA) analysis, was significantly (P < 0.001) different in the soil receiving the residue mixture, compared to the average structures of the communities in soil receiving four individual residues. Differences in the biomass of fungi, general bacteria, and Gram-positive bacteria were responsible for the observed synergistic effect of crop residue mixtures on total microbial biomass and residue-derived microbial biomass, especially biomarkers 16:0, 18:2ω6 and 18:3ω3. Our study demonstrates that applying a mixture of crop residues increases soil microbial biomass to a greater extent than would be expected from applying individual residues and that this occurs either due to faster decomposition of the crop residues or greater carbon use efficiency (CUE), rather than priming the decomposition of native SOM. Therefore, growing crop polycultures (e.g., cover crop mixtures) and incorporating mixtures of the resulting crop residues into the soil could be an effective method to increase microbial biomass and ultimately C stocks in arable soils.

Three Different Approaches Based on Derivative Ratio Spectra for Spectrophotometric Resolution of Quaternary Mixture in Semisolid Dosage Form

Background Recent incorporated spectrophotometer software supporting mathematical methods was considered as an optimum key for the resolution of multicomponent mixtures. Objective Several spectrophotometric techniques are introduced for the determination of mixtures of Tretinoin (TN), Hydroquinone (HQ), and Fluocinolone acetonide (FA), in presence of the preservative; Methyl Paraben (MP), without any separation procedure, taking into consideration the presence of two minor components and the severe overlap of their spectra. Methods Constant multiplication coupled spectrum subtraction resolved the quaternary mixture into the zero-order absorption spectrum of TN alone and a severely overlapped ternary mixture of HQ, FA, and MP. Three approaches based on the derivative ratio spectra were applied to resolve this ternary severely overlapped mixture which are: derivative ration zero-crossing point method, factorized derivative ratio method, and double divisor derivative ratio method. Results The work is conducted over a concentration range of 1–10, 4–38, and 4–35 µg/mL, for TN, HQ, and FA, respectively. The results obtained are compared statistically to each other and to the official methods showing no significant difference. Conclusions The proposed methods are successfully applied for the simultaneous determination of the three drugs in presence of MP in synthetic mixtures and in their combined dosage form Trimelasma® cream with very good accuracy and precision. Highlights Comparative study between conventional and new methods for resolving ternary severely overlapped mixtures. Mathematical manipulation steps and enrichment techniques aided accurate quantification of the minor components in mixture.

Analysis of candlenut oil as oil adulterant in three functional oils of soybean oil, sunflower oil and grapeseed oil in quaternary mixture systems using FTIR spectroscopy and chemometrics

Soybean oil (SBO), sunflower oil (SFO) and grapeseed oil (GPO) contain high levels of unsaturated fats that are good for health and have proximity to candlenut oil. Candlenut oil (CNO) has a lower price and easier to get oil from that seeds than other seed oils, so it is used as adulteration for gains. Therefore, authentication is required to ensure the purity of oils by proper analysis. This research was aimed to highlight the FTIR spectroscopy application with multivariate calibration is a potential analysis for scanning the quaternary mixture of CNO, SBO, SFO and GPO. CNO quantification was performed using multivariate calibrations of principle component (PCR) regression and partial least (PLS) square to predict the model from the optimization FTIR spectra regions. The highest R2 and the lowest values of root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were used as the basis for selection of multivariate calibrations created using several wavenumbers region of FTIR spectra. Wavenumbers regions of 4000-650 cm-1 from the second derivative FTIR-ATR spectra using PLS was used for quantitative analysis of CNO in quaternary mixture with SBO, SFO and GPO with R2 calibration = 0.9942 and 0.0239% for RMSEC value and 0.0495%. So, it can be concluded the use of FTIR spectra combination with PLS is accurate to detect quaternary mixtures of CNO, SBO, SFO and GPO with the highest R2 values and the lowest RMSEC and RMSEP values.