The synergistic effects of rosehip oil and matrine against Icerya aegyptiaca (Douglas) (Hemiptera: Coccoidea) and the underlying mechanisms

Matrine induces cardiotoxicity by promoting ferroptosis through the Nrf2 antioxidant system in H9c2 cells

Matrine (MT) has shown promising efficacy in various cancers and chronic hepatitis; however, its clinical application is limited because of its side effects. Our previous studies have indicated that MT can induce severe hepatotoxicity and nephrotoxicity. The current study aimed to investigate its cardiotoxicity and potential underlying mechanisms in H9c2 cells. Our results showed that MT induced H9c2 cell death and disrupted the cellular membrane integrity. Moreover, MT decreased glutathione (GSH) and cysteine (Cys) levels, and increased Fe2+, lipid peroxidation, reactive oxygen species (ROS), and MDA levels, ultimately leading to ferroptosis. Interestingly, these phenomena were alleviated by the ferroptosis inhibitor Fer-1, whereas MT-induced ferroptosis was exacerbated by the ferroptosis agonist RSL3. In addition, MT significantly reduced FTH, Nrf2, xCT, GPX4, and FSP1 protein levels and inhibited the transcriptional activity of Nrf2 while increasing TFR1 protein levels. Supplementation with Nrf2 agonist (Dimethyl fumarate, DMF) or selenium (Sodium selenite, SS) and CoQ10 alleviated MT-induced cytotoxic effects in H9c2 cells. These results suggest that ferroptosis, which is mediated by an imbalance in the Nrf2 antioxidant system, is involved in MT-induced cardiac toxicity.

Metabolism, digestion, and horizontal transfer: potential roles and interaction of symbiotic bacteria in the ladybird beetle Novius pumilus and their prey Icerya aegyptiaca

In this study, we first time sequenced and analyzed the 16S rRNA gene data of predator ladybird beetles Novius pumilus and globally distributed invasive pest Icerya aegyptiaca at different stages, and combined data with bacterial genome sequences in N. pumilus to explored the taxonomic distribution, alpha and beta diversity, differentially abundant bacteria, co-occurrence network, and putative functions of their microbial community. Our finding revealed that Candidatus Walczuchella, which exhibited a higher abundance in I. aegyptiaca, possessed several genes in essential amino acid biosynthesis and seemed to perform roles in providing nutrients to the host, similar to other obligate symbionts in scale insects. Lactococcus, Serratia, and Pseudomonas, more abundant in N. pumilus, were predicted to have genes related to hydrocarbon, fatty acids, and chitin degradation, which may assist their hosts in digesting the wax shell covering the scale insects. Notably, our result showed that Lactococcus had relatively higher abundances in adults and eggs compared to other stages in N. pumilus, indicating potential vertical transmission. Additionally, we found that Arsenophonus, known to influence sex ratios in whitefly and wasp, may also function in I. aegyptiaca, probably by influencing nutrient metabolism as it similarly had many genes corresponding to vitamin B and essential amino acid biosynthesis. Also, we observed a potential horizontal transfer of Arsenophonus between the scale insect and its predator, with a relatively high abundance in the ladybirds compared to other bacteria from the scale insects.IMPORTANCEThe composition and dynamic changes of microbiome in different developmental stages of ladybird beetles Novius pumilus with its prey Icerya aegyptiaca were detected. We found that Candidatus Walczuchella, abundant in I. aegyptiaca, probably provide nutrients to their host based on their amino acid biosynthesis-related genes. Abundant symbionts in N. pumilus, including Lactococcus, Serratia, and Pseudophonus, may help the host digest the scale insects with their hydrocarbon, fatty acid, and chitin degrading-related genes. A key endosymbiont Arsenophonus may play potential roles in the nutrient metabolisms and sex determination in I. aegyptiaca, and is possibly transferred from the scale insect to the predator.

Synthesis, antibacterial activity, and 3D-QASR studies of matrine-indole derivatives as potential antibiotics

Matrine and indole have antibacterial, anticancer, and other biological activities, in order to develop new antibiotics to solve the problem of multi-drug resistant bacteria. In this paper, we synthesized a series of 29 novel matrine derivatives as potential drug candidates by combining indole analogs and matrine. The antibacterial activity of these compounds was evaluated through minimum inhibitory concentration (MIC) assays against five bacterial strains (S. aureus, C. albicans, P. acnes, P. aeruginosa, and E. coli). The obtained results demonstrated promising antibacterial efficacy, particularly for compounds A20 and A18, which exhibited MICs.au values of 0.021 and 0.031 mg/ml, respectively, against S. aureus. Moreover, compounds A20 and A27 displayed remarkable MICc.al values of 2.806 and 4.519 mg/ml, respectively, against C. albicans, surpassing the performance of the clinical antibiotic penicillin G sodium (0.0368 mg/ml) and fluconazole (4.849 mg/ml). These findings underscore the significant bacteriostatic activity of the matrine derivatives. Furthermore, to gain a deeper understanding 3D-QSAR modeling was employed, revealing the critical influence of steric structure, charge distribution, hydrophobic interactions, and hydrogen bonding within the molecular structure on the bacteriostatic activity of the compounds. Additionally, molecular docking simulations shed light on the interaction between compound A20 and bacterial proteins, highlighting the involvement of hydrogen bonding, hydrophobic interactions, and π-π conjugation in the formation of stable complexes that inhibit the normal functioning of the proteins. This comprehensive analysis provided valuable insights into the antibacterial mechanism of the novel matrine derivatives, offering theoretical support for their potential application as antibiotics.

Cuticular property affects the insecticidal synergy of major constituents in thyme oil against houseflies, Musca domestica

Plant essential oils are intricate blends comprising predominantly of monoterpenes and some sesquiterpenes. These oils display diverse bioactivities against targeted organisms, often arising from complex interactions among their constituents, which may demonstrate synergistic or antagonistic effects. Despite their wide use as botanical insecticides, the mechanisms behind these interactions and their effects on bioactivity are poorly understood. This study investigated the synergistic interaction of thymol and p-cymene, two major constituents of Thymus vulgaris essential oil, on the larvae and adults of the housefly, Musca domestica. The results showed that p-cymene synergized the insecticidal activity of thymol in adult houseflies, but not in larvae. GC-MS analyses and bioassays indicated the increased cuticular penetration of thymol by p-cymene was the mechanism of synergy, which was observed only in the adults. Two potential routes were proposed: the expansion of the wetting area, or the disruption of cuticular integrity through dissolving the wax layer. The sequential application and large-volume treatment bioassay results suggested that the former was the more likely mechanism. Also, the hydrophobicity of the cuticle seemed critical for this stage-specific synergy. Wax-devoid adults failed to show synergistic toxicity, whereas artificially wax-coated larvae gained a synergistic effect. Overall, the findings provide insights into the synergistic mechanism of insecticidal activity of plant essential oils and suggest potential applications in developing effective strategies using penetration-enhancing synergists.

Matrine can be absorbed and transmitted bidirectionally to defend against aphids (Hemiptera: Aphididae) on wheat and pepper

BACKGROUND

Although matrine is widely used, its absorption and transport mechanisms in crops remain unexplored. In this study, three methods including foliar application, hydroponics and seed immersion were used to investigate whether matrine molecules could enter into plants through different channels, and to further resolve its transport characteristics. The systemic activity of matrine also was evaluated.

RESULT

Matrine was quickly absorbed and transported downwards after the leaves of wheat or peppers were treated, and also accumulated and transmitted upwards by roots. It was not only absorbed by seeds, but also appeared continuously in young roots and leaves in both plants for nearly 20 days. There were some differences in the uptake and conduction of matrine between pepper and wheat: matrine concentrated in pepper upper leaves with less delivered downwards to roots than in wheat, and also transduction of matrine in pepper lower leaves upwards to upper leaves was less than in wheat. Matrine had systemic activity, with LC50 of 361.99 and 904.24 μg·mL-1 against Rhopalosiphum padib on wheat and Myzus persicae (Sulzer) on pepper plants at 48 h, separately.

CONCLUSION

Matrine can be absorbed by the roots, seeds and leaves of plants, and transmitted bidirectionally to any organs, presenting satisfactory systemic poisoning activity against aphids. It is of great significance to develop new formulation products of matrine and promote its commercialized value. © 2023 Society of Chemical Industry.

The transcriptome of Icerya aegyptiaca (Hemiptera: Monophlebidae) and comparison with neococcoids reveal genetic clues of evolution in the scale insects

BACKGROUND

Scale insects are worldwide sap-sucking parasites, which can be distinguished into neococcoids and non-neococcoids. Neococcoids are monophyletic with a peculiar reproductive system, paternal genome elimination (PGE). Different with neococcoids, Iceryini, a tribe in non-neococcoids including several damaging pests, has abdominal spiracles, compound eyes in males, relatively abundant wax, unique hermaphrodite system, and specific symbionts. However, the current studies on the gene resources and genomic mechanism of scale insects are mainly limited in the neococcoids, and lacked of comparison in an evolution frame.

RESULT

We sequenced and de novo assembled a transcriptome of Icerya aegyptiaca (Douglas), a worldwide pest of Iceryini, and used it as representative of non-neococcoids to compare with the genomes or transcriptomes of other six species from different families of neococcoids. We found that the genes under positive selection or negative selection intensification (simplified as "selected genes" below) in I. aegyptiaca included those related to neurogenesis and development, especially eye development. Some genes related to fatty acid biosynthesis were unique in its transcriptome with relatively high expression and not detected in neococcoids. These results may indicate a potential link to the unique structures and abundant wax of I. aegyptiaca compared with neococcoids. Meanwhile, genes related to DNA repair, mitosis, spindle, cytokinesis and oogenesis, were included in the selected genes in I. aegyptiaca, which is possibly associated with cell division and germ cell formation of the hermaphrodite system. Chromatin-related process were enriched from selected genes in neococcoids, along with some mitosis-related genes also detected, which may be related to their unique PGE system. Moreover, in neococcoid species, male-biased genes tend to undergo negative selection relaxation under the PGE system. We also found that the candidate horizontally transferred genes (HTGs) in the scale insects mainly derived from bacteria and fungi. bioD and bioB, the two biotin-synthesizing HTGs were exclusively found in the scale insects and neococcoids, respectively, which possibly show potential demand changes in the symbiotic relationships.

CONCLUSION

Our study reports the first I. aegyptiaca transcriptome and provides preliminary insights for the genetic change of structures, reproductive systems and symbiont relationships at an evolutionary aspect. This will provide a basis for further research and control of scale insects.

Pest categorisation of Icerya aegyptiaca

The EFSA Panel on Plant Health performed a pest categorisation of Icerya aegyptiaca (Hemiptera: Sternorrhyncha: Monophlebidae), the Egyptian fluted scale, for the EU. This insect is established in several countries in tropical and subtropical regions of the world. Within the EU, the pest has not been reported. It is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is highly polyphagous, feeding on plants in 128 genera and 66 families, with some preference for avocado (Persea americana), banana (Musa sp.), citrus (Citrus spp.), coconut (Coccos nucifera), common pear (Pyrus communis), fig (Ficus spp.), guava (Psidium guajava), maize (Zea mays), mango (Mangifera indica), white mulberry (Morus alba), and grapevine (Vitis vinifera). It has also been recorded feeding on tomato (Solanum lycopersicum), as well as on ornamental plants. Plants for planting and fruits, vegetables and cut flowers are the main potential pathways for entry of I. aegyptiaca into the EU. Climatic conditions and availability of host plants in parts of the EU where there are very few days of frost each year would likely allow this species to successfully establish and spread. Economic impact in cultivated hosts including citrus, grapes, maize, peppers, sunflowers, tomatoes and ornamental crops is anticipated if establishment occurs. Phytosanitary measures are available to reduce the likelihood of entry and spread. I. aegyptiaca meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.