Analysis of glutathione-S-transferases from larvae of Galleria mellonella (Lepidoptera, Pyralidae) with potential alkaloid detoxification function.

The greater wax moth, Galleria mellonella, is a global pest for beehives, doing damage in the larval stage. Although a significant number of studies have reported on larvae and adults, to date no effective pest control has been implemented. In this study, we tested larval resistance to alkaloids from Berberis microphylla, and the objective was to identify enzymes that participate in alkaloid detoxification through enzymatic assays, bioinformatics analysis and qRT-PCR. Findings suggest glutathione-S-transferases (GSTs), from an increased metabolic mechanism, are responsible for alkaloid detoxification rather than cytochrome P450 (CYP), carboxylesterases (CarE). A bioinformatics analysis from transcriptome data revealed 22 GSTs present in both G. mellonella larvae and adults. The qRT-PCR experiments corroborated the presence of the 22 GSTs in larvae, where GST8 and GST20 stood out with the highest expression after berberine treatment. Structural information around GST8 and GST20 suggests that GST8 could bind berberine stronger than GST20. These findings represent an important advance in the study of detoxification enzymes in G. mellonella, expanding the role of delta-class GSTs towards alkaloids. Likewise, GST inhibition by alkaloid analogs is proposed in the framework of integrated pest management strategies.

Antibacterial Activity of Alkaloid Fractions from Berberis microphylla G. Forst and Study of Synergism with Ampicillin and Cephalothin.

Berberis microphylla is a native plant that grows in Patagonia and is commonly used by aboriginal ethnic groups in traditional medicine as an antiseptic for different diseases. The present study evaluated the antibacterial and synergistic activity of alkaloid extracts of B. microphylla leaves, stems and roots used either individually or in combination with antibiotics against Gram-positive and Gram-negative bacteria. The in vitro antibacterial activities of leaf, stem and root alkaloid extracts had significant activity only against Gram-positive bacteria. Disc diffusion tests demonstrated that the root extract showed similar activity against B. cereus and S. epidermidis compared to commercial antibiotics, namely ampicillin and cephalothin, and pure berberine, the principal component of the alkaloid extracts, was found to be active only against S. aureus and S. epidermidis with similar activity to that of the root extract. The minimum inhibitory concentrations (MICs) of the alkaloid extracts ranged from 333 to 83 µg/mL, whereas minimum bactericidal concentrations (MBCs) varied from 717 to 167 µg/mL. In addition, synergistic or indifferent effects between the alkaloid extracts and antibiotics against bacterial strains were confirmed.

Identification of isoquinoline alkaloids from Berberis microphylla by HPLC ESI-MS/MS / Identificación de alcaloides isoquinolínicos en Berberis microphylla G. Forst mediante CLAE IES-MS/MS

Berberis microphylla (G. Forst) is a native plant growing in Patagonia. In recent years Patagonia Berberis are becoming important due to their interesting biological properties related to their alkaloids content. The aim of this study was determine the distribution and proportion of isoquinoline alkaloids in leaves, stems and roots of B. microphylla collected in two different climatic zones from Chilean Patagonia. Using by HPLC ESI-MS/MS isocorydine, jatrorrhizine, palmatine, reticuline, scoulerine, tetrahydroberberine and thalifendine were detected for the first time in this specie, and the presence of allocryptopine, berberine, calafatine and protopine, previously isolated in B. microphylla was corroborated. The alkaloids profile showed differences of compounds in samples collected in two climatic zones, where more compounds were detected in plants from Lago Deseado than Cerro Sombrero. Furthermore, a greater number of alkaloids were found in stem and root extracts and berberine and thalifendine were detected in higher proportion in these structures.

Berberis microphylla (G. Forst) es un arbusto nativo que crece en la Patagonia. Actualmente, esta planta ha sido foco de estudio dada las propiedades biológicas que presenta, atribuidas principalmente al contenido de alcaloides. El objetivo de este estudio fue determinar la distribución y proporción de alcaloides isoquinolínicos en hojas, tallos y raíces de B. microphylla colectadas en dos zonas climáticas de la Patagonia chilena. Mediante CLAE IES-MS/MS se informa por primera vez la presencia de isocoridina jatrorrizina, palmatina, reticulina, escoulerina, tetrahidroberberina y talifendina en esta especie y se confirma la presencia de allocriptopina, berberina, calafatina y protopina, identificados previamente en B. microphylla. El perfil de alcaloides mostró diferencias en la presencia de compuestos en las muestras colectas en las dos zonas climáticas, observándose un mayor número de compuestos en plantas provenientes de Lago Deseado. Además, un mayor número de compuestos se identificó en extractos de tallos y raíces donde berberina y talifendina fueron detectados en mayor proporción.

Electroantennographic and behavioral responses of adults of raspberry weevil Aegorhinus superciliosus (Coleoptera: Curculionidae) to odors released from conspecific females.

The raspberry weevil, Aegorhinus superciliosus (Guérin) (Coleoptera: Curculionidae), is the most important pest in blueberry and raspberry fields in the south of Chile. In this study, we investigated the electroantennographic and behavioral responses of A. superciliosus to semiochemicals released from conspecific individual adults, with particular attention to male attraction to females. Odors released from females significantly attracted males in a Y-tube olfactometer. Gas chromatographic and mass spectral analysis of female volatile extracts revealed the presence of limonene and α-pinene. Electroantennogram recordings from both sexes indicated that males of A. superciliosus possess olfactory sensitivity for the R isomer of limonene and α-pinene, whereas females only perceived R-limonene. Behavioral assays using synthetic compounds showed that only R-limonene elicited an attraction response from male weevils. Field experiments confirmed the laboratory results, showing that R-limonene was attractive to weevils. This is the first report of intraspecific chemical communication in this weevil. We discuss the origin of these compounds, their possible role in the sexual behavior of this species, and their potential use in a pest control strategy.