Development and evaluation of emulsifiable concentrate formulation containing Sophora alopecuroides L. extract for the novel management of Asian citrus psyllid

Identification and characterization of a promiscuous metallohydrolase in metallo-β-lactamase superfamily from a locally isolated organophosphate-degrading Bacillus sp. strain S3wahi

In this present study, characteristics and structure-function relationship of an organophosphate-degrading enzyme from Bacillus sp. S3wahi were described. S3wahi metallohydrolase, designated as S3wahi-MH (probable metallohydrolase YqjP), featured the conserved αβ/βα metallo-β-lactamase-fold (MBL-fold) domain and a zinc bimetal at its catalytic site. The metal binding site of S3wahi-MH also preserves the H-X-H-X-D-H motif, consisting of specific amino acids at Zn1 (Asp69, His70, Asp182, and His230) and Zn2 (His65, His67, and His137). The multifunctionality of S3wahi-MH was demonstrated through a steady-state kinetic study, revealing its highest binding affinity (KM) and catalytic efficiency (kcat/KM) for OP compound, paraoxon, with values of 8.09 × 10-6 M and 4.94 × 105 M-1 s-1, respectively. Using OP compound, paraoxon, as S3wahi-MH native substrate, S3wahi-MH exhibited remarkable stability over a broad temperature range, 20 °C - 60 °C and a broad pH tolerance, pH 6-10. Corresponded to S3wahi-MH thermal stability characterization, the estimated melting temperature (Tm) was found to be 72.12 °C. S3wahi-MH was also characterized with optimum catalytic activity at 30 °C and pH 8. Additionally, the activity of purified S3wahi-MH was greatly enhanced in the presence of 1 mM and 5 mM of manganese (Mn2+), showing relative activities of 1323.68 % and 2073.68 %, respectively. The activity of S3wahi-MH was also enhanced in the presence of DMSO and DMF, showing relative activities of 270.37 % and 307.41 %, respectively. The purified S3wahi-MH retained >60 % residual activity after exposure to non-ionic Tween series surfactants. Nevertheless, the catalytic activity of S3wahi-MH was severely impacted by the treatment of SDS, even at low concentrations. Considering its enzymatic properties and promiscuity, S3wahi-MH emerges as a promising candidate as a bioremediation tool in wide industrial applications, including agriculture industry.

Enhance the physicochemical properties of the citronella oil -SLNPs to improve the insecticidal activity against Spodoptera littoralis (Boisd) (Lep. Nactuidae)

The Nano-formulation of citronella essential oil (Cymbopogon nardus (L.) and their mixtures of three adjuvants (Provecta®, Top film®, and PEG600-dioleate) were studied to enhance physico-chemical properties of the Nano-formulation and improve the insecticidal effect against Spodoptera littoralis (Boisd). Characterisation of physicochemical properties of Nano-formulation was studied by calculating droplet size, polydispersity index (PDI), and Zeta-potential parameters. The results showed that the Solid Lipid Nanoparticles (SLNs) mixtures of three adjuvant mixtures had more toxic activity and stability than the Nano-formulation alone. Before storage the acidity, alkalinity (pH), and viscosity exhibited an acidic pH value in the range (4.11-5.34), whereas after three months of storage was recorded high pH, a shift in the pH on storage can indicate the instability of active substances or product under semi field-laboratory conditions. Nano-formulation of the citronella oil mixed with the three adjuvants increased the mortality percentage of S. littoralis larvae.

Effect of Brucea javanica Oil on the Toxicity of β-Cypermethrin Emulsifiable Concentrate Formulation

Enhancing the performance of traditional pesticide formulations by improving their leaf surface wetting capabilities is a crucial approach for maximizing the pesticide efficiency. This study develops an emulsifiable concentrate (EC) of 4.5% β-cypermethrin containing Brucea javanica oil (BJO). The incorporation of BJO aims to improve the leaf-wetting properties of the EC formulation and enhance its insecticidal effectiveness. The droplet size and emulsion characteristics of β-CYP EC emulsion with varying concentrations of the emulsifier were evaluated, and changes after incorporating BJO were assessed to develop the optimal formulation. A comprehensive comparison was conducted among commercial 4.5% β-cypermethrin EC (β-CYP EC-1), 4.5% β-cypermethrin EC with BJO (β-CYP EC-2), and 4.5% β-cypermethrin EC without BJO (β-CYP EC-3). This comparison encompassed various factors including storage stability, insecticidal activity, cytotoxicity, and wetting performance on cabbage leaves. The results indicated that the ideal emulsifier concentration was 15% emulsifier 0201B. β-CYP EC-2 demonstrated superior wetting properties on cabbage leaves (the wetting performance of β-CYP EC-2 emulsion on cabbage leaves is 2.60 times that of the β-CYP EC-1 emulsion), heightened insecticidal activity against the third larvae of Plutella xylostella [diamondback moth (DBM)] [the insecticidal activity of the β-CYP EC-2 emulsion against the third larvae of DBM is 1.93 times that of the β-CYP EC-1 emulsion (12 h)], and more obvious inhibitory effects on the proliferation of DBM embryo cells than the other tested formulations. These findings have significant implications for advancing pest control strategies and promoting sustainable and effective agricultural practices.

Profiling and quantitation of alkaloids in different parts of Sophora alopecuroides L. extracts by high-performance liquid chromatography with electrospray ionisation ion mobility spectrometry detection

INTRODUCTION

Ambient pressure electrospray ionisation ion mobility spectrometry coupled to high-performance liquid chromatography (HPLC) was used to detect alkaloids from different parts of Sophora alopecuroides L. extracts. Multiplexing ion mobility spectrometry (IMS) was used to improve the signal-to-noise ratio while maintaining high resolving power for the detecting of eluents from HPLC separation.

MATERIAL AND METHODS

The alkaloids profile and distribution are demonstrated by retention time-drift time two-dimensional spaces, and the contents of five major alkaloids including sophoridine, sophocarpine, cytisine, aloperine, and matrine were determined in the leaf, skin, stem, seed kernel, and seed husk using the HPLC-IMS method. This method offers extra separation ability to isomers such as matrine and sophocarpine, which can be difficult to distinguish by mass spectrometry.

RESULTS

The reduced mobilities for cytisine, sophoridine, sophocarpine, matrine, and aloperine are 0.828, 0.718, 0.731, 0.725, and 0.769 cm² /V/s, respectively. The limits of detection are 0.553, 0.488, 0.479, 0.484, and 0.513 ug/mL. This method adds extra separation ability to HPLC to resolve co-eluted peaks and provides another qualitative parameter besides HPLC retention time.

Metarhizium Anisopliae Challenges Immunity and Demography of Plutella xylostella

Simple Summary

The diamondback moth, Plutella xylostella, is a destructive pest of cruciferous crops worldwide. Integrated pest management (IPM) strategies, largely involve the use chemical pesticides which are harmful for the environment and human health. In this study, the virulence of three species of entomopathogenic fungi were tested. Metarhizium anisopliae proved to be the most effective by killing more than 90% of the population. Based on which the fungus was selected to study the host-pathogen immune interactions. More precisely, after infection, superoxide dismutase (SOD) and phenoloxidase (PO), two major enzymes involved in immune response, were studied at different time points. The fungus gradually weakened the enzyme activities as the time progressed, indicating that physiological attributes of host were adversely affected. The expression of immune-related genes (Defensin, Spaetzle, Cecropin, Lysozyme, and Hemolin) varied on different time points. Moreover, the fungus negatively impacted the development of the host by reducing the life span and egg laying ability. Thus, M. anisopliae can become a potent prospect for the control of this pest. This information will also reinforce the development of policies for biocontrol-based pest management.

Abstract

Entomopathogenic fungi are naturally existing microbes, that can serve as a key regulator of insect pests in integrated pest management strategies. Besides having no hazardous effects on the environment, these entomopathogens are alternatives to synthetic insecticides that can control notorious insect-like Plutella xylostella, a destructive pest of cruciferous crops. Three different species of entomopathogenic fungi were evaluated before the selection (high larval mortality and least LC₅₀) of Metarhizum anisopliae. The study was designed to investigate the mortality, development, and immune responses of P. xylostella when challenged with M. anisopliae, a naturally existing soil-borne entomopathogenic fungus. M. anisopliae resulted in high pest mortality by killing 93% of larvae. However, no statistically significant effect on hemocyte concentration was observed. The activity of enzymes (Phenoloxidase and Superoxide dismutase) and immune genes (Defensin, Spaetzle, Cecropin, Lysozyme, and Hemolin) did vary at different time points (24, 48, 72 and 96 h) after exposure to M. anisopliae. Disturbance in the biological cycles of P. xylostella was also detected, significantly shorter adult life span (8.11:6.87, M:F) and reduced fecundity (101 eggs/female) were observed along with disturbed larval and pupal duration. Results suggest that M. anisopliae can efficiently hinder the P. xylostella defense and developmental system, resulting in mortality and disturbed demography.

Larvicidal, Ovicidal, Synergistic, and Repellent Activities of Sophora alopecuroides and Its Dominant Constituents Against Aedes albopictus

In the current study, to combat insecticide resistance, we explored larvicidal, ovicidal, synergistic, and repellent activities of Sophora alopecuroides extract and its dominant constituents against Aedes albopictus. The results of the toxicity bioassays demonstrated that the extract of S. alopecuroides exerted significant larvicidal activity (16.66-86.66%) against the third-instar larvae of Ae. albopictus at different concentrations (5-50 ug/mL) and low hatchability of eggs (2.32-75%) at 5-50 ug/mL. The constituents of S. alopecuroides showed a synergistic effect when applied as a mixture (LC30 + LC30) against larvae, while no synergistic effect was observed against the eggs of Ae. albopictus. S. alopecuroides extract provided 93.11% repellency in the first 90 min and gradually decreased to 53.14% after 240 min, while the positive control DEET (N,N-diethyl-3-methylbenzamide) showed 94.18% in the first 90 min and 55.33% after 240 min. All of the results exhibited a concentration-dependent effect. To the best of our knowledge, this is the first time that a study has identified a highly effective extract of S. alopecuroides, which could be used as an alternative agent to control larvae and eggs and to repel adults of Ae. albopictus.